move examples to examples directory

14 files changed, 1880 insertions, 0 deletions

diff --git a/examples/example_4bit_palette.cpp b/examples/example_4bit_palette.cpp
new file mode 100644
index 0000000..f495cca
--- /dev/null
+++ b/examples/example_4bit_palette.cpp
@@ -0,0 +1,106 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+//g++ lodepng.cpp example_4bit_palette.cpp -ansi -pedantic -Wall -Wextra -O3
+
+
+
+/*
+LodePNG 4-bit palette example.
+This example encodes a 511x511 PNG with a 4-bit palette.
+Both image and palette contain sine waves, resulting in a sort of plasma.
+The 511 (rather than power of two 512) size is of course chosen on purpose to
+confirm that scanlines not filling up an entire byte size are working.
+
+NOTE: a PNG image with a translucent palette is perfectly valid. However there
+exist some programs that cannot correctly read those, including, surprisingly,
+Gimp 2.8 image editor (until you set mode to RGB).
+*/
+
+#include <cmath>
+#include <iostream>
+
+#include "lodepng.h"
+
+int main(int argc, char *argv[])
+{
+  //check if user gave a filename
+  if(argc < 2)
+  {
+    std::cout << "please provide a filename to save to" << std::endl;
+    return 0;
+  }
+
+  //create encoder and set settings and info (optional)
+  lodepng::State state;
+  
+  //generate palette
+  for(int i = 0; i < 16; i++)
+  {
+    unsigned char r = 127 * (1 + std::sin(5 * i * 6.28318531 / 16));
+    unsigned char g = 127 * (1 + std::sin(2 * i * 6.28318531 / 16));
+    unsigned char b = 127 * (1 + std::sin(3 * i * 6.28318531 / 16));
+    unsigned char a = 63 * (1 + std::sin(8 * i * 6.28318531 / 16)) + 128; /*alpha channel of the palette (tRNS chunk)*/
+    
+    //palette must be added both to input and output color mode, because in this
+    //sample both the raw image and the expected PNG image use that palette.
+    lodepng_palette_add(&state.info_png.color, r, g, b, a);
+    lodepng_palette_add(&state.info_raw, r, g, b, a);
+  }
+  
+  //both the raw image and the encoded image must get colorType 3 (palette)
+  state.info_png.color.colortype = LCT_PALETTE; //if you comment this line, and create the above palette in info_raw instead, then you get the same image in a RGBA PNG.
+  state.info_png.color.bitdepth = 4;
+  state.info_raw.colortype = LCT_PALETTE;
+  state.info_raw.bitdepth = 4;
+  state.encoder.auto_convert = 0; //we specify ourselves exactly what output PNG color mode we want
+  
+  //generate some image
+  const unsigned w = 511;
+  const unsigned h = 511;
+  std::vector<unsigned char> image;
+  image.resize((w * h * 4 + 7) / 8, 0);
+  for(unsigned y = 0; y < h; y++)
+  for(unsigned x = 0; x < w; x++)
+  {
+    size_t byte_index = (y * w + x) / 2;
+    bool byte_half = (y * w + x) % 2 == 1;
+    
+    int color = (int)(4 * ((1 + std::sin(2.0 * 6.28318531 * x / (double)w))
+                         + (1 + std::sin(2.0 * 6.28318531 * y / (double)h))) );
+
+    image[byte_index] |= (unsigned char)(color << (byte_half ? 0 : 4));
+  }
+  
+  //encode and save
+  std::vector<unsigned char> buffer;
+  unsigned error = lodepng::encode(buffer, image.empty() ? 0 : &image[0], w, h, state);
+  if(error)
+  {
+    std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+  lodepng::save_file(buffer, argv[1]);
+}
diff --git a/examples/example_bmp2png.cpp b/examples/example_bmp2png.cpp
new file mode 100644
index 0000000..c6bdd24
--- /dev/null
+++ b/examples/example_bmp2png.cpp
@@ -0,0 +1,134 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2010 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+/*
+Load a BMP image and convert it to a PNG image. This example also shows how
+to use other data with the same memory structure as BMP, such as the image
+format native to win32, GDI (HBITMAP, BITMAPINFO, ...) often encountered if
+you're programming for Windows in Visual Studio.
+
+This example only supports uncompressed 24-bit RGB or 32-bit RGBA bitmaps.
+For other types of BMP's, use a full fledged BMP decoder, or convert the
+bitmap to 24-bit or 32-bit format.
+
+NOTE: it overwrites the output file without warning if it exists!
+*/
+
+//g++ lodepng.cpp example_bmp2png.cpp -ansi -pedantic -Wall -Wextra -O3
+
+#include "lodepng.h"
+
+#include <iostream>
+
+//returns 0 if all went ok, non-0 if error
+//output image is always given in RGBA (with alpha channel), even if it's a BMP without alpha channel
+unsigned decodeBMP(std::vector<unsigned char>& image, unsigned& w, unsigned& h, const std::vector<unsigned char>& bmp)
+{
+  static const unsigned MINHEADER = 54; //minimum BMP header size
+  
+  if(bmp.size() < MINHEADER) return -1;
+  if(bmp[0] != 'B' || bmp[1] != 'M') return 1; //It's not a BMP file if it doesn't start with marker 'BM'
+  unsigned pixeloffset = bmp[10] + 256 * bmp[11]; //where the pixel data starts
+  //read width and height from BMP header
+  w = bmp[18] + bmp[19] * 256;
+  h = bmp[22] + bmp[23] * 256;
+  //read number of channels from BMP header
+  if(bmp[28] != 24 && bmp[28] != 32) return 2; //only 24-bit and 32-bit BMPs are supported.
+  unsigned numChannels = bmp[28] / 8;
+
+  //The amount of scanline bytes is width of image times channels, with extra bytes added if needed
+  //to make it a multiple of 4 bytes.
+  unsigned scanlineBytes = w * numChannels;
+  if(scanlineBytes % 4 != 0) scanlineBytes = (scanlineBytes / 4) * 4 + 4;
+
+  unsigned dataSize = scanlineBytes * h;
+  if(bmp.size() < dataSize + pixeloffset) return 3; //BMP file too small to contain all pixels
+
+  image.resize(w * h * 4);
+
+  /*
+  There are 3 differences between BMP and the raw image buffer for LodePNG:
+  -it's upside down
+  -it's in BGR instead of RGB format (or BRGA instead of RGBA)
+  -each scanline has padding bytes to make it a multiple of 4 if needed
+  The 2D for loop below does all these 3 conversions at once.
+  */
+  for(unsigned y = 0; y < h; y++)
+  for(unsigned x = 0; x < w; x++)
+  {
+    //pixel start byte position in the BMP
+    unsigned bmpos = pixeloffset + (h - y - 1) * scanlineBytes + numChannels * x;
+    //pixel start byte position in the new raw image
+    unsigned newpos = 4 * y * w + 4 * x;
+    if(numChannels == 3)
+    {
+      image[newpos + 0] = bmp[bmpos + 2]; //R
+      image[newpos + 1] = bmp[bmpos + 1]; //G
+      image[newpos + 2] = bmp[bmpos + 0]; //B
+      image[newpos + 3] = 255;            //A
+    }
+    else
+    {
+      image[newpos + 0] = bmp[bmpos + 3]; //R
+      image[newpos + 1] = bmp[bmpos + 2]; //G
+      image[newpos + 2] = bmp[bmpos + 1]; //B
+      image[newpos + 3] = bmp[bmpos + 0]; //A
+    }
+  }
+  return 0;
+}
+
+int main(int argc, char *argv[])
+{
+  if(argc < 3)
+  {
+    std::cout << "Please provice input PNG and output BMP file names" << std::endl;
+    return 0;
+  }
+
+  std::vector<unsigned char> bmp;
+  lodepng::load_file(bmp, argv[1]);
+  std::vector<unsigned char> image;
+  unsigned w, h;
+  unsigned error = decodeBMP(image, w, h, bmp);
+
+  if(error)
+  {
+    std::cout << "BMP decoding error " << error << std::endl;
+    return 0;
+  }
+  
+  std::vector<unsigned char> png;
+  error = lodepng::encode(png, image, w, h);
+
+  if(error)
+  {
+    std::cout << "PNG encoding error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+  
+  lodepng::save_file(png, argv[2]);
+  
+}
diff --git a/examples/example_decode.c b/examples/example_decode.c
new file mode 100644
index 0000000..1ecec3d
--- /dev/null
+++ b/examples/example_decode.c
@@ -0,0 +1,113 @@
+/*

+LodePNG Examples

+

+Copyright (c) 2005-2012 Lode Vandevenne

+

+This software is provided 'as-is', without any express or implied

+warranty. In no event will the authors be held liable for any damages

+arising from the use of this software.

+

+Permission is granted to anyone to use this software for any purpose,

+including commercial applications, and to alter it and redistribute it

+freely, subject to the following restrictions:

+

+    1. The origin of this software must not be misrepresented; you must not

+    claim that you wrote the original software. If you use this software

+    in a product, an acknowledgment in the product documentation would be

+    appreciated but is not required.

+

+    2. Altered source versions must be plainly marked as such, and must not be

+    misrepresented as being the original software.

+

+    3. This notice may not be removed or altered from any source

+    distribution.

+*/

+

+#include "lodepng.h"

+

+#include <stdio.h>

+#include <stdlib.h>

+

+/*

+3 ways to decode a PNG from a file to RGBA pixel data (and 2 in-memory ways).

+*/

+

+/*

+Example 1

+Decode from disk to raw pixels with a single function call

+*/

+void decodeOneStep(const char* filename)

+{

+  unsigned error;

+  unsigned char* image;

+  unsigned width, height;

+

+  error = lodepng_decode32_file(&image, &width, &height, filename);

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+

+  /*use image here*/

+

+  free(image);

+}

+

+/*

+Example 2

+Load PNG file from disk to memory first, then decode to raw pixels in memory.

+*/

+void decodeTwoSteps(const char* filename)

+{

+  unsigned error;

+  unsigned char* image;

+  unsigned width, height;

+  unsigned char* png;

+  size_t pngsize;

+

+  lodepng_load_file(&png, &pngsize, filename);

+  error = lodepng_decode32(&image, &width, &height, png, pngsize);

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+

+  free(png);

+

+  /*use image here*/

+

+  free(image);

+}

+

+/*

+Example 3

+Load PNG file from disk using a State, normally needed for more advanced usage.

+*/

+void decodeWithState(const char* filename)

+{

+  unsigned error;

+  unsigned char* image;

+  unsigned width, height;

+  unsigned char* png;

+  size_t pngsize;

+  LodePNGState state;

+

+  lodepng_state_init(&state);

+  /*optionally customize the state*/

+

+  lodepng_load_file(&png, &pngsize, filename);

+  error = lodepng_decode(&image, &width, &height, &state, png, pngsize);

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+

+  free(png);

+

+  /*use image here*/

+  /*state contains extra information about the PNG such as text chunks, ...*/

+

+  lodepng_state_cleanup(&state);

+  free(image);

+}

+

+int main(int argc, char *argv[])

+{

+  const char* filename = argc > 1 ? argv[1] : "test.png";

+

+  decodeOneStep(filename);

+  

+  return 0;

+}

+

diff --git a/examples/example_decode.cpp b/examples/example_decode.cpp
new file mode 100644
index 0000000..4eee6b8
--- /dev/null
+++ b/examples/example_decode.cpp
@@ -0,0 +1,95 @@
+/*

+LodePNG Examples

+

+Copyright (c) 2005-2012 Lode Vandevenne

+

+This software is provided 'as-is', without any express or implied

+warranty. In no event will the authors be held liable for any damages

+arising from the use of this software.

+

+Permission is granted to anyone to use this software for any purpose,

+including commercial applications, and to alter it and redistribute it

+freely, subject to the following restrictions:

+

+    1. The origin of this software must not be misrepresented; you must not

+    claim that you wrote the original software. If you use this software

+    in a product, an acknowledgment in the product documentation would be

+    appreciated but is not required.

+

+    2. Altered source versions must be plainly marked as such, and must not be

+    misrepresented as being the original software.

+

+    3. This notice may not be removed or altered from any source

+    distribution.

+*/

+

+#include "lodepng.h"

+#include <iostream>

+

+/*

+3 ways to decode a PNG from a file to RGBA pixel data (and 2 in-memory ways).

+*/

+

+//g++ lodepng.cpp example_decode.cpp -ansi -pedantic -Wall -Wextra -O3

+

+

+//Example 1

+//Decode from disk to raw pixels with a single function call

+void decodeOneStep(const char* filename)

+{

+  std::vector<unsigned char> image; //the raw pixels

+  unsigned width, height;

+

+  //decode

+  unsigned error = lodepng::decode(image, width, height, filename);

+

+  //if there's an error, display it

+  if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;

+

+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...

+}

+

+//Example 2

+//Load PNG file from disk to memory first, then decode to raw pixels in memory.

+void decodeTwoSteps(const char* filename)

+{

+  std::vector<unsigned char> png;

+  std::vector<unsigned char> image; //the raw pixels

+  unsigned width, height;

+

+  //load and decode

+  lodepng::load_file(png, filename);

+  unsigned error = lodepng::decode(image, width, height, png);

+

+  //if there's an error, display it

+  if(error) std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;

+

+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...

+}

+

+//Example 3

+//Load PNG file from disk using a State, normally needed for more advanced usage.

+void decodeWithState(const char* filename)

+{

+  std::vector<unsigned char> png;

+  std::vector<unsigned char> image; //the raw pixels

+  unsigned width, height;

+  lodepng::State state; //optionally customize this one

+

+  lodepng::load_file(png, filename); //load the image file with given filename

+  unsigned error = lodepng::decode(image, width, height, state, png);

+

+  //if there's an error, display it

+  if(error) std::cout << "decoder error " << error << ": "<< lodepng_error_text(error) << std::endl;

+

+  //the pixels are now in the vector "image", 4 bytes per pixel, ordered RGBARGBA..., use it as texture, draw it, ...

+  //State state contains extra information about the PNG such as text chunks, ...

+}

+

+int main(int argc, char *argv[])

+{

+  const char* filename = argc > 1 ? argv[1] : "test.png";

+

+  decodeOneStep(filename);

+}

+

diff --git a/examples/example_encode.c b/examples/example_encode.c
new file mode 100644
index 0000000..0e0f8bf
--- /dev/null
+++ b/examples/example_encode.c
@@ -0,0 +1,116 @@
+/*

+LodePNG Examples

+

+Copyright (c) 2005-2012 Lode Vandevenne

+

+This software is provided 'as-is', without any express or implied

+warranty. In no event will the authors be held liable for any damages

+arising from the use of this software.

+

+Permission is granted to anyone to use this software for any purpose,

+including commercial applications, and to alter it and redistribute it

+freely, subject to the following restrictions:

+

+    1. The origin of this software must not be misrepresented; you must not

+    claim that you wrote the original software. If you use this software

+    in a product, an acknowledgment in the product documentation would be

+    appreciated but is not required.

+

+    2. Altered source versions must be plainly marked as such, and must not be

+    misrepresented as being the original software.

+

+    3. This notice may not be removed or altered from any source

+    distribution.

+*/

+

+#include "lodepng.h"

+

+#include <stdio.h>

+#include <stdlib.h>

+

+/*

+3 ways to encode a PNG from RGBA pixel data to a file (and 2 in-memory ways).

+NOTE: this samples overwrite the file or test.png without warning!

+*/

+

+/*

+Example 1

+Encode from raw pixels to disk with a single function call

+The image argument has width * height RGBA pixels or width * height * 4 bytes

+*/

+void encodeOneStep(const char* filename, const unsigned char* image, unsigned width, unsigned height)

+{

+  /*Encode the image*/

+  unsigned error = lodepng_encode32_file(filename, image, width, height);

+

+  /*if there's an error, display it*/

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+}

+

+/*

+Example 2

+Encode from raw pixels to an in-memory PNG file first, then write it to disk

+The image argument has width * height RGBA pixels or width * height * 4 bytes

+*/

+void encodeTwoSteps(const char* filename, const unsigned char* image, unsigned width, unsigned height)

+{

+  unsigned char* png;

+  size_t pngsize;

+

+  unsigned error = lodepng_encode32(&png, &pngsize, image, width, height);

+  if(!error) lodepng_save_file(png, pngsize, filename);

+

+  /*if there's an error, display it*/

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+

+  free(png);

+}

+

+/*

+Example 3

+Save a PNG file to disk using a State, normally needed for more advanced usage.

+The image argument has width * height RGBA pixels or width * height * 4 bytes

+*/

+void encodeWithState(const char* filename, const unsigned char* image, unsigned width, unsigned height)

+{

+  unsigned error;

+  unsigned char* png;

+  size_t pngsize;

+  LodePNGState state;

+

+  lodepng_state_init(&state);

+  /*optionally customize the state*/

+

+  error = lodepng_encode(&png, &pngsize, image, width, height, &state);

+  if(!error) lodepng_save_file(png, pngsize, filename);

+

+  /*if there's an error, display it*/

+  if(error) printf("error %u: %s\n", error, lodepng_error_text(error));

+

+  lodepng_state_cleanup(&state);

+  free(png);

+}

+

+int main(int argc, char *argv[])

+{

+  const char* filename = argc > 1 ? argv[1] : "test.png";

+

+  /*generate some image*/

+  unsigned width = 512, height = 512;

+  unsigned char* image = malloc(width * height * 4);

+  unsigned x, y;

+  for(y = 0; y < height; y++)

+  for(x = 0; x < width; x++)

+  {

+    image[4 * width * y + 4 * x + 0] = 255 * !(x & y);

+    image[4 * width * y + 4 * x + 1] = x ^ y;

+    image[4 * width * y + 4 * x + 2] = x | y;

+    image[4 * width * y + 4 * x + 3] = 255;

+  }

+

+  /*run an example*/

+  encodeOneStep(filename, image, width, height);

+

+  free(image);

+  return 0;

+}

diff --git a/examples/example_encode.cpp b/examples/example_encode.cpp
new file mode 100644
index 0000000..31dd0b8
--- /dev/null
+++ b/examples/example_encode.cpp
@@ -0,0 +1,97 @@
+/*

+LodePNG Examples

+

+Copyright (c) 2005-2012 Lode Vandevenne

+

+This software is provided 'as-is', without any express or implied

+warranty. In no event will the authors be held liable for any damages

+arising from the use of this software.

+

+Permission is granted to anyone to use this software for any purpose,

+including commercial applications, and to alter it and redistribute it

+freely, subject to the following restrictions:

+

+    1. The origin of this software must not be misrepresented; you must not

+    claim that you wrote the original software. If you use this software

+    in a product, an acknowledgment in the product documentation would be

+    appreciated but is not required.

+

+    2. Altered source versions must be plainly marked as such, and must not be

+    misrepresented as being the original software.

+

+    3. This notice may not be removed or altered from any source

+    distribution.

+*/

+

+#include "lodepng.h"

+#include <iostream>

+

+/*

+3 ways to encode a PNG from RGBA pixel data to a file (and 2 in-memory ways).

+NOTE: this samples overwrite the file or test.png without warning!

+*/

+

+//g++ lodepng.cpp example_encode.cpp -ansi -pedantic -Wall -Wextra -O3

+

+//Example 1

+//Encode from raw pixels to disk with a single function call

+//The image argument has width * height RGBA pixels or width * height * 4 bytes

+void encodeOneStep(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height)

+{

+  //Encode the image

+  unsigned error = lodepng::encode(filename, image, width, height);

+

+  //if there's an error, display it

+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;

+}

+

+//Example 2

+//Encode from raw pixels to an in-memory PNG file first, then write it to disk

+//The image argument has width * height RGBA pixels or width * height * 4 bytes

+void encodeTwoSteps(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height)

+{

+  std::vector<unsigned char> png;

+

+  unsigned error = lodepng::encode(png, image, width, height);

+  if(!error) lodepng::save_file(png, filename);

+

+  //if there's an error, display it

+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;

+}

+

+//Example 3

+//Save a PNG file to disk using a State, normally needed for more advanced usage.

+//The image argument has width * height RGBA pixels or width * height * 4 bytes

+void encodeWithState(const char* filename, std::vector<unsigned char>& image, unsigned width, unsigned height)

+{

+  std::vector<unsigned char> png;

+  lodepng::State state; //optionally customize this one

+

+  unsigned error = lodepng::encode(png, image, width, height, state);

+  if(!error) lodepng::save_file(png, filename);

+

+  //if there's an error, display it

+  if(error) std::cout << "encoder error " << error << ": "<< lodepng_error_text(error) << std::endl;

+}

+

+//saves image to filename given as argument. Warning, this overwrites the file without warning!

+int main(int argc, char *argv[])

+{

+  //NOTE: this sample will overwrite the file or test.png without warning!

+  const char* filename = argc > 1 ? argv[1] : "test.png";

+

+  //generate some image

+  unsigned width = 512, height = 512;

+  std::vector<unsigned char> image;

+  image.resize(width * height * 4);

+  for(unsigned y = 0; y < height; y++)

+  for(unsigned x = 0; x < width; x++)

+  {

+    image[4 * width * y + 4 * x + 0] = 255 * !(x & y);

+    image[4 * width * y + 4 * x + 1] = x ^ y;

+    image[4 * width * y + 4 * x + 2] = x | y;

+    image[4 * width * y + 4 * x + 3] = 255;

+  }

+

+  encodeOneStep(filename, image, width, height);

+}

diff --git a/examples/example_gzip.cpp b/examples/example_gzip.cpp
new file mode 100644
index 0000000..b2ddf17
--- /dev/null
+++ b/examples/example_gzip.cpp
@@ -0,0 +1,93 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+#include "lodepng.h"
+#include <iostream>
+#include <stdlib.h>
+
+/*
+Encodes given file as a gzip file.
+
+See also the gzip specification, RFC 1952: http://www.gzip.org/zlib/rfc-gzip.html
+*/
+
+//g++ lodepng.cpp example_gzip.cpp -ansi -pedantic -Wall -Wextra -O3
+
+//saves image to filename given as argument. Warning, this overwrites the file without warning!
+int main(int argc, char *argv[])
+{
+  if(argc < 2)
+  {
+    std::cout << "Please provide input filename (output is input with .gz)" << std::endl;
+    return 0;
+  }
+  
+  //NOTE: this sample will overwrite the output file without warning!
+  std::string infilename = argv[1];
+  std::string outfilename = infilename + ".gz";
+  
+  std::vector<unsigned char> in;
+  lodepng::load_file(in, infilename);
+  
+  size_t outsize = 10;
+  unsigned char* out = (unsigned char*)malloc(outsize);
+  out[0] = 31;  //ID1
+  out[1] = 139; //ID2
+  out[2] = 8; //CM
+  out[3] = 0; //FLG
+  //MTIME
+  out[4] = 0;
+  out[5] = 0;
+  out[6] = 0;
+  out[7] = 0;
+
+  out[8] = 2; //2 = slow, 4 = fast compression
+  out[9] = 255; //OS unknown
+  
+  lodepng_deflate(&out, &outsize, &in[0], in.size(), &lodepng_default_compress_settings);
+  
+  unsigned crc = lodepng_crc32(&in[0], in.size());
+  
+  size_t footer = outsize;
+  
+  outsize += 8;
+  out = (unsigned char*)realloc(out, outsize);
+  
+  //CRC
+  out[footer + 0] = crc % 256;
+  out[footer + 1] = (crc >> 8) % 256;
+  out[footer + 2] = (crc >> 16) % 256;
+  out[footer + 3] = (crc >> 24) % 256;
+
+  //ISIZE
+  out[footer + 4] = in.size() % 256;
+  out[footer + 5] = (in.size() >> 8) % 256;
+  out[footer + 6] = (in.size() >> 16) % 256;
+  out[footer + 7] = (in.size() >> 24) % 256;
+  
+  lodepng_save_file(out, outsize, outfilename.c_str());
+  
+  free(out);
+}
diff --git a/examples/example_opengl.cpp b/examples/example_opengl.cpp
new file mode 100644
index 0000000..1879864
--- /dev/null
+++ b/examples/example_opengl.cpp
@@ -0,0 +1,162 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+//Compile command for Linux:
+//g++ lodepng.cpp example_opengl.cpp -lSDL -lGL -O3
+
+/*
+LodePNG OpenGL example. Decodes a PNG and shows it in OpenGL. PNG filename
+should be given as a command line parameter.
+
+It's written for the most basic old OpenGL version, and a correction for non
+power of two textures had to be added.
+
+Only very few lines on the sample are about loading the PNG. Most of the
+sample lines show a way to render a texture in 2D in OpenGL.
+
+No fancy 3D graphics are shown, it only shows the image statically. The sample
+shows LodePNG can be used to load PNG images as textures in OpenGL.
+*/
+
+#include "lodepng.h"
+
+#include <iostream>
+#include <SDL/SDL.h>
+#include <GL/gl.h>
+
+int main(int argc, char *argv[])
+{
+  if(argc < 2)
+  {
+    std::cout << "Please provide a filename." << std::endl;
+    return 1;
+  }
+  const char* filename = argv[1];
+
+  // Load file and decode image.
+  std::vector<unsigned char> image;
+  unsigned width, height;
+  unsigned error = lodepng::decode(image, width, height, filename);
+
+  // If there's an error, display it.
+  if(error != 0)
+  {
+    std::cout << "error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 1;
+  }
+  
+  // Here the PNG is loaded in "image". All the rest of the code is SDL and OpenGL stuff.
+
+  int screenw = width;
+  if(screenw > 1024) screenw = 1024;
+  int screenh = height;
+  if(screenh > 768) screenw = 768;
+
+  if(SDL_Init(SDL_INIT_VIDEO) < 0)
+  {
+    std::cout << "Error: Unable to init SDL: " << SDL_GetError() << std::endl;
+    return 1;
+  }
+  
+  SDL_Surface* scr = SDL_SetVideoMode(screenw, screenh, 32, SDL_OPENGL);
+
+  if(scr == 0)
+  {
+    std::cout << "Error: Unable to set video. SDL error message: " << SDL_GetError() << std::endl;
+    return 1;
+  }
+
+  // The official code for "Setting Your Raster Position to a Pixel Location" (i.e. set up a camera for 2D screen)
+  glViewport(0, 0, screenw, screenh);
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  glOrtho(0, screenw, screenh, 0, -1, 1);
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+
+  // Make some OpenGL properties better for 2D and enable alpha channel.
+  glDisable(GL_CULL_FACE);
+  glDisable(GL_DEPTH_TEST);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glEnable(GL_BLEND);
+  glDisable(GL_ALPHA_TEST);
+
+  if(glGetError() != GL_NO_ERROR)
+  {
+    std::cout << "Error initing GL" << std::endl;
+    return 1;
+  }
+  
+  // Texture size must be power of two for the primitive OpenGL version this is written for. Find next power of two.
+  size_t u2 = 1; while(u2 < width) u2 *= 2;
+  size_t v2 = 1; while(v2 < height) v2 *= 2;
+  // Ratio for power of two version compared to actual version, to render the non power of two image with proper size.
+  double u3 = (double)width / u2;
+  double v3 = (double)height / v2;
+
+  // Make power of two version of the image.
+  std::vector<unsigned char> image2(u2 * v2 * 4);
+  for(size_t y = 0; y < height; y++)
+  for(size_t x = 0; x < width; x++)
+  for(size_t c = 0; c < 4; c++)
+  {
+    image2[4 * u2 * y + 4 * x + c] = image[4 * width * y + 4 * x + c];
+  }
+  
+  // Enable the texture for OpenGL.
+  glEnable(GL_TEXTURE_2D);
+  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); //GL_NEAREST = no smoothing
+  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  glTexImage2D(GL_TEXTURE_2D, 0, 4, u2, v2, 0, GL_RGBA, GL_UNSIGNED_BYTE, &image2[0]);
+  
+  bool done = false;
+  SDL_Event event = {0};
+  glColor4ub(255, 255, 255, 255);
+  
+  while(!done)
+  {
+    // Quit the loop when receiving quit event.
+    while(SDL_PollEvent(&event))
+    {
+      if(event.type == SDL_QUIT) done = 1;
+    }
+    
+    // Draw the texture on a quad, using u3 and v3 to correct non power of two texture size.
+    glBegin(GL_QUADS);
+      glTexCoord2d( 0,  0); glVertex2f(    0,      0);
+      glTexCoord2d(u3,  0); glVertex2f(width,      0);
+      glTexCoord2d(u3, v3); glVertex2f(width, height);
+      glTexCoord2d( 0, v3); glVertex2f(    0, height);
+    glEnd();
+    
+    // Redraw and clear screen.
+    SDL_GL_SwapBuffers();
+    glClearColor(0, 0, 0, 0);
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+    
+    //Limit frames per second, to not heat up the CPU and GPU too much.
+    SDL_Delay(16);
+  }
+}
diff --git a/examples/example_optimize_png.cpp b/examples/example_optimize_png.cpp
new file mode 100644
index 0000000..ecf25cf
--- /dev/null
+++ b/examples/example_optimize_png.cpp
@@ -0,0 +1,133 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+/*
+This example saves the PNG with the best compression LodePNG can do, and with
+unnecesary chunks removed. It tries out several combinations of settings and
+keeps the smallest one.
+
+NOTE: This is not as good as a true PNG optimizer like optipng or pngcrush.
+*/
+
+//g++ lodepng.cpp example_optimize_png.cpp -ansi -pedantic -Wall -Wextra -O3
+
+#include "lodepng.h"
+
+#include <iostream>
+
+int main(int argc, char *argv[])
+{
+  std::vector<unsigned char> image;
+  unsigned w, h;
+  std::vector<unsigned char> buffer;
+  unsigned error;
+  
+  //check if user gave a filename
+  if(argc < 3)
+  {
+    std::cout << "please provide in and out filename" << std::endl;
+    return 0;
+  }
+  
+  lodepng::load_file(buffer, argv[1]);
+  error = lodepng::decode(image, w, h, buffer);
+
+  if(error)
+  {
+    std::cout << "decoding error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+  
+  size_t origsize = buffer.size();
+  std::cout << "Original size: " << origsize << " (" << (origsize / 1024) << "K)" << std::endl;
+  buffer.clear();
+  
+  //Now encode as hard as possible with several filter types and window sizes
+  
+  lodepng::State state;
+  state.encoder.filter_palette_zero = 0; //We try several filter types, including zero, allow trying them all on palette images too.
+  state.encoder.add_id = false; //Don't add LodePNG version chunk to save more bytes
+  state.encoder.text_compression = 1; //Not needed because we don't add text chunks, but this demonstrates another optimization setting
+  state.encoder.zlibsettings.nicematch = 258; //Set this to the max possible, otherwise it can hurt compression
+  state.encoder.zlibsettings.lazymatching = 1; //Definitely use lazy matching for better compression
+  state.encoder.zlibsettings.windowsize = 32768; //Use maximum possible window size for best compression
+
+  size_t bestsize = 0;
+  bool inited = false;
+
+  int beststrategy = 0;
+  LodePNGFilterStrategy strategies[4] = { LFS_ZERO, LFS_MINSUM, LFS_ENTROPY, LFS_BRUTE_FORCE };
+  std::string strategynames[4] = { "LFS_ZERO", "LFS_MINSUM", "LFS_ENTROPY", "LFS_BRUTE_FORCE" };
+
+  // min match 3 allows all deflate lengths. min match 6 is similar to "Z_FILTERED" of zlib.
+  int minmatches[2] = { 3, 6 };
+  int bestminmatch = 0;
+  
+  int autoconverts[2] = { 0, 1 };
+  std::string autoconvertnames[2] = { "0", "1" };
+  int bestautoconvert = 0;
+
+  int bestblocktype = 0;
+
+  // Try out all combinations of everything
+  for(int i = 0; i < 4; i++) //filter strategy
+  for(int j = 0; j < 2; j++) //min match
+  for(int k = 0; k < 2; k++) //block type (for small images only)
+  for(int l = 0; l < 2; l++) //color convert strategy
+  {
+    if(bestsize > 3000 && (k > 0 || l > 0)) continue; /* these only make sense on small images */
+    std::vector<unsigned char> temp;
+    state.encoder.filter_strategy = strategies[i];
+    state.encoder.zlibsettings.minmatch = minmatches[j];
+    state.encoder.zlibsettings.btype = k == 0 ? 2 : 1;
+    state.encoder.auto_convert = autoconverts[l];
+    error = lodepng::encode(temp, image, w, h, state);
+
+    if(error)
+    {
+      std::cout << "encoding error " << error << ": " << lodepng_error_text(error) << std::endl;
+      return 0;
+    }
+
+    if(!inited || temp.size() < bestsize)
+    {
+      bestsize = temp.size();
+      beststrategy = i;
+      bestminmatch = state.encoder.zlibsettings.minmatch;
+      bestautoconvert = l;
+      bestblocktype = state.encoder.zlibsettings.btype;
+      temp.swap(buffer);
+      inited = true;
+    }
+  }
+  
+  std::cout << "Chosen filter strategy: " << strategynames[beststrategy] << std::endl;
+  std::cout << "Chosen min match: " << bestminmatch << std::endl;
+  std::cout << "Chosen block type: " << bestblocktype << std::endl;
+  std::cout << "Chosen auto convert: " << autoconvertnames[bestautoconvert] << std::endl;
+  
+  lodepng::save_file(buffer, argv[2]);
+  std::cout << "New size: " << buffer.size() << " (" << (buffer.size() / 1024) << "K)" << std::endl;
+}
diff --git a/examples/example_png2bmp.cpp b/examples/example_png2bmp.cpp
new file mode 100644
index 0000000..3fd8328
--- /dev/null
+++ b/examples/example_png2bmp.cpp
@@ -0,0 +1,132 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+#include "lodepng.h"
+#include <iostream>
+
+/*
+This example converts a PNG file to a BMP file.
+NOTE: it overwrites the output file without warning if it exists!
+Give the PNG and the BMP file names as command line arguments.
+*/
+
+/*
+g++ lodepng.cpp example_png2bmp.cpp -Wall -Wextra -pedantic -ansi -lSDL -O3
+*/
+
+
+
+//Input image must be RGB buffer (3 bytes per pixel), but you can easily make it
+//support RGBA input and output by changing the inputChannels and/or outputChannels
+//in the function to 4.
+void encodeBMP(std::vector<unsigned char>& bmp, const unsigned char* image, int w, int h)
+{
+  //3 bytes per pixel used for both input and output.
+  int inputChannels = 3;
+  int outputChannels = 3;
+  
+  //bytes 0-13
+  bmp.push_back('B'); bmp.push_back('M'); //0: bfType
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); //2: bfSize; size not yet known for now, filled in later.
+  bmp.push_back(0); bmp.push_back(0); //6: bfReserved1
+  bmp.push_back(0); bmp.push_back(0); //8: bfReserved2
+  bmp.push_back(54 % 256); bmp.push_back(54 / 256); bmp.push_back(0); bmp.push_back(0); //10: bfOffBits (54 header bytes)
+
+  //bytes 14-53
+  bmp.push_back(40); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //14: biSize
+  bmp.push_back(w % 256); bmp.push_back(w / 256); bmp.push_back(0); bmp.push_back(0); //18: biWidth
+  bmp.push_back(h % 256); bmp.push_back(h / 256); bmp.push_back(0); bmp.push_back(0); //22: biHeight
+  bmp.push_back(1); bmp.push_back(0); //26: biPlanes
+  bmp.push_back(outputChannels * 8); bmp.push_back(0); //28: biBitCount
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //30: biCompression
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //34: biSizeImage
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //38: biXPelsPerMeter
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //42: biYPelsPerMeter
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //46: biClrUsed
+  bmp.push_back(0); bmp.push_back(0); bmp.push_back(0); bmp.push_back(0);  //50: biClrImportant
+  
+  /*
+  Convert the input RGBRGBRGB pixel buffer to the BMP pixel buffer format. There are 3 differences with the input buffer:
+  -BMP stores the rows inversed, from bottom to top
+  -BMP stores the color channels in BGR instead of RGB order
+  -BMP requires each row to have a multiple of 4 bytes, so sometimes padding bytes are added between rows
+  */
+
+  int imagerowbytes = outputChannels * w;
+  imagerowbytes = imagerowbytes % 4 == 0 ? imagerowbytes : imagerowbytes + (4 - imagerowbytes % 4); //must be multiple of 4
+  
+  for(int y = h - 1; y >= 0; y--) //the rows are stored inversed in bmp
+  {
+    int c = 0;
+    for(int x = 0; x < imagerowbytes; x++)
+    {
+      if(x < w * outputChannels)
+      {
+        int inc = c;
+        //Convert RGB(A) into BGR(A)
+        if(c == 0) inc = 2;
+        else if(c == 2) inc = 0;
+        bmp.push_back(image[inputChannels * (w * y + x / outputChannels) + inc]);
+      }
+      else bmp.push_back(0);
+      c++;
+      if(c >= outputChannels) c = 0;
+    }
+  }
+
+  // Fill in the size
+  bmp[2] = bmp.size() % 256;
+  bmp[3] = (bmp.size() / 256) % 256;
+  bmp[4] = (bmp.size() / 65536) % 256;
+  bmp[5] = bmp.size() / 16777216;
+}
+
+int main(int argc, char *argv[])
+{
+  if(argc < 3)
+  {
+    std::cout << "Please provice input PNG and output BMP file names" << std::endl;
+    return 0;
+  }
+  const char* infile = argv[1];
+  const char* outfile = argv[2];
+  
+  
+  std::vector<unsigned char> image; //the raw pixels
+  unsigned width, height;
+
+  unsigned error = lodepng::decode(image, width, height, infile, LCT_RGB, 8);
+
+  if(error)
+  {
+    std::cout << "error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+
+  std::vector<unsigned char> bmp;
+  encodeBMP(bmp, &image[0], width, height);
+  
+  lodepng::save_file(bmp, outfile);
+}
diff --git a/examples/example_png_info.cpp b/examples/example_png_info.cpp
new file mode 100644
index 0000000..cd2eca6
--- /dev/null
+++ b/examples/example_png_info.cpp
@@ -0,0 +1,349 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+//g++ lodepng.cpp example_png_info.cpp -ansi -pedantic -Wall -Wextra -lSDL -O3
+
+/*
+This sample shows a lot of information in the console about a PNG file,
+including color type, text chunks, the names of all chunks in the image,
+etc...
+*/
+
+
+#include "lodepng.h"
+#include <iostream>
+
+/*
+Display general info about the PNG.
+*/
+void displayPNGInfo(const LodePNGInfo& info)
+{
+  const LodePNGColorMode& color = info.color;
+
+  std::cout << "Compression method: " << info.compression_method << std::endl;
+  std::cout << "Filter method: " << info.filter_method << std::endl;
+  std::cout << "Interlace method: " << info.interlace_method << std::endl;
+  std::cout << "Color type: " << color.colortype << std::endl;
+  std::cout << "Bit depth: " << color.bitdepth << std::endl;
+  std::cout << "Bits per pixel: " << lodepng_get_bpp(&color) << std::endl;
+  std::cout << "Channels per pixel: " << lodepng_get_channels(&color) << std::endl;
+  std::cout << "Is greyscale type: " << lodepng_is_greyscale_type(&color) << std::endl;
+  std::cout << "Can have alpha: " << lodepng_can_have_alpha(&color) << std::endl;
+  std::cout << "Palette size: " << color.palettesize << std::endl;
+  std::cout << "Has color key: " << color.key_defined << std::endl;
+  if(color.key_defined)
+  {
+    std::cout << "Color key r: " << color.key_r << std::endl;
+    std::cout << "Color key g: " << color.key_g << std::endl;
+    std::cout << "Color key b: " << color.key_b << std::endl;
+  }
+  std::cout << "Texts: " << info.text_num << std::endl;
+  for(size_t i = 0; i < info.text_num; i++)
+  {
+    std::cout << "Text: " << info.text_keys[i] << ": " << info.text_strings[i] << std::endl << std::endl;
+  }
+  std::cout << "International texts: " << info.itext_num << std::endl;
+  for(size_t i = 0; i < info.itext_num; i++)
+  {
+    std::cout << "Text: "
+              << info.itext_keys[i] << ", "
+              << info.itext_langtags[i] << ", "
+              << info.itext_transkeys[i] << ": "
+              << info.itext_strings[i] << std::endl << std::endl;
+  }
+  std::cout << "Time defined: " << info.time_defined << std::endl;
+  if(info.time_defined)
+  {
+    const LodePNGTime& time = info.time;
+    std::cout << "year: " << time.year << std::endl;
+    std::cout << "month: " << time.month << std::endl;
+    std::cout << "day: " << time.day << std::endl;
+    std::cout << "hour: " << time.hour << std::endl;
+    std::cout << "minute: " << time.minute << std::endl;
+    std::cout << "second: " << time.second << std::endl;
+  }
+  std::cout << "Physics defined: " << info.phys_defined << std::endl;
+  if(info.phys_defined)
+  {
+    std::cout << "physics X: " << info.phys_x << std::endl;
+    std::cout << "physics Y: " << info.phys_y << std::endl;
+    std::cout << "physics unit: " << info.phys_unit << std::endl;
+  }
+}
+
+
+/*
+Display the names and sizes of all chunks in the PNG file.
+*/
+void displayChunkNames(const std::vector<unsigned char>& buffer)
+{
+  // Listing chunks is based on the original file, not the decoded png info.
+  const unsigned char *chunk, *begin, *end, *next;
+  end = &buffer.back() + 1;
+  begin = chunk = &buffer.front() + 8;
+
+  std::cout << std::endl << "Chunks:" << std::endl;
+  std::cout << " type: length(s)";
+  std::string last_type;
+  while(chunk + 8 < end && chunk >= begin)
+  {
+    char type[5];
+    lodepng_chunk_type(type, chunk);
+    if(std::string(type).size() != 4)
+    {
+      std::cout << "this is probably not a PNG" << std::endl;
+      return;
+    }
+
+    if(last_type != type)
+    {
+      std::cout << std::endl;
+      std::cout << " " << type << ": ";
+    }
+    last_type = type;
+
+    std::cout << lodepng_chunk_length(chunk) << ", ";
+
+    next = lodepng_chunk_next_const(chunk);
+    if (next <= chunk) break; // integer overflow
+    chunk = next;
+  }
+  std::cout << std::endl;
+}
+
+
+/*
+Show ASCII art preview of the image
+*/
+void displayAsciiArt(const std::vector<unsigned char>& image, unsigned w, unsigned h)
+{
+  if(w > 0 && h > 0)
+  {
+    std::cout << std::endl << "ASCII Art Preview: " << std::endl;
+    unsigned w2 = 48;
+    if(w < w2) w2 = w;
+    unsigned h2 = h * w2 / w;
+    h2 = (h2 * 2) / 3; //compensate for non-square characters in terminal
+    if(h2 > (w2 * 2)) h2 = w2 * 2; //avoid too large output
+
+    std::cout << '+';
+    for(unsigned x = 0; x < w2; x++) std::cout << '-';
+    std::cout << '+' << std::endl;
+    for(unsigned y = 0; y < h2; y++)
+    {
+      std::cout << "|";
+      for(unsigned x = 0; x < w2; x++)
+      {
+        unsigned x2 = x * w / w2;
+        unsigned y2 = y * h / h2;
+        int r = image[y2 * w * 4 + x2 * 4 + 0];
+        int g = image[y2 * w * 4 + x2 * 4 + 1];
+        int b = image[y2 * w * 4 + x2 * 4 + 2];
+        int a = image[y2 * w * 4 + x2 * 4 + 3];
+        int lightness = ((r + g + b) / 3) * a / 255;
+        int min = (r < g && r < b) ? r : (g < b ? g : b);
+        int max = (r > g && r > b) ? r : (g > b ? g : b);
+        int saturation = max - min;
+        int letter = 'i'; //i for grey, or r,y,g,c,b,m for colors
+        if(saturation > 32)
+        {
+          int h = lightness >= (min + max) / 2;
+          if(h) letter = (min == r ? 'c' : (min == g ? 'm' : 'y'));
+          else letter = (max == r ? 'r' : (max == g ? 'g' : 'b'));
+        }
+        int symbol = ' ';
+        if(lightness > 224) symbol = '@';
+        else if(lightness > 128) symbol = letter - 32;
+        else if(lightness > 32) symbol = letter;
+        else if(lightness > 16) symbol = '.';
+        std::cout << (char)symbol;
+      }
+      std::cout << "|";
+      std::cout << std::endl;
+    }
+    std::cout << '+';
+    for(unsigned x = 0; x < w2; x++) std::cout << '-';
+    std::cout << '+' << std::endl;
+  }
+}
+
+
+/*
+Show the filtertypes of each scanline in this PNG image.
+*/
+void displayFilterTypes(const std::vector<unsigned char>& buffer, bool ignore_checksums)
+{
+  //Get color type and interlace type
+  lodepng::State state;
+  if(ignore_checksums)
+  {
+    state.decoder.ignore_crc = 1;
+    state.decoder.zlibsettings.ignore_adler32 = 1;
+  }
+  unsigned w, h;
+  unsigned error;
+  error = lodepng_inspect(&w, &h, &state, &buffer[0], buffer.size());
+
+  if(error)
+  {
+    std::cout << "inspect error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return;
+  }
+
+  if(state.info_png.interlace_method == 1)
+  {
+    std::cout << "showing filtertypes for interlaced PNG not supported by this example" << std::endl;
+    return;
+  }
+
+  //Read literal data from all IDAT chunks
+  const unsigned char *chunk, *begin, *end, *next;
+  end = &buffer.back() + 1;
+  begin = chunk = &buffer.front() + 8;
+
+  std::vector<unsigned char> zdata;
+
+  while(chunk + 8 < end && chunk >= begin)
+  {
+    char type[5];
+    lodepng_chunk_type(type, chunk);
+    if(std::string(type).size() != 4)
+    {
+      std::cout << "this is probably not a PNG" << std::endl;
+      return;
+    }
+
+    if(std::string(type) == "IDAT")
+    {
+      const unsigned char* cdata = lodepng_chunk_data_const(chunk);
+      unsigned clength = lodepng_chunk_length(chunk);
+      if(chunk + clength + 12 > end || clength > buffer.size() || chunk + clength + 12 < begin) {
+        std::cout << "invalid chunk length" << std::endl;
+        return;
+      }
+
+      for(unsigned i = 0; i < clength; i++)
+      {
+        zdata.push_back(cdata[i]);
+      }
+    }
+
+    next = lodepng_chunk_next_const(chunk);
+    if (next <= chunk) break; // integer overflow
+    chunk = next;
+  }
+
+  //Decompress all IDAT data
+  std::vector<unsigned char> data;
+  error = lodepng::decompress(data, &zdata[0], zdata.size());
+
+  if(error)
+  {
+    std::cout << "decompress error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return;
+  }
+
+  //A line is 1 filter byte + all pixels
+  size_t linebytes = 1 + lodepng_get_raw_size(w, 1, &state.info_png.color);
+
+  if(linebytes == 0)
+  {
+    std::cout << "error: linebytes is 0" << std::endl;
+    return;
+  }
+
+  std::cout << "Filter types: ";
+  for(size_t i = 0; i < data.size(); i += linebytes)
+  {
+    std::cout << (int)(data[i]) << " ";
+  }
+  std::cout << std::endl;
+
+}
+
+
+/*
+Main
+*/
+int main(int argc, char *argv[]) /*list the chunks*/
+{
+  bool ignore_checksums = false;
+  std::string filename = "";
+  for (int i = 1; i < argc; i++)
+  {
+    if(std::string(argv[i]) == "--ignore_checksums") ignore_checksums = true;
+    else filename = argv[i];
+  }
+  if(filename == "")
+  {
+    std::cout << "Please provide a filename to preview" << std::endl;
+    return 0;
+  }
+
+  std::vector<unsigned char> buffer;
+  std::vector<unsigned char> image;
+  unsigned w, h;
+
+  lodepng::load_file(buffer, filename); //load the image file with given filename
+
+  lodepng::State state;
+  if(ignore_checksums)
+  {
+    state.decoder.ignore_crc = 1;
+    state.decoder.zlibsettings.ignore_adler32 = 1;
+  }
+
+  unsigned error = lodepng::decode(image, w, h, state, buffer);
+
+  if(error)
+  {
+    std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+
+  std::cout << "Filesize: " << buffer.size() << " (" << buffer.size() / 1024 << "K)" << std::endl;
+  std::cout << "Width: " << w << std::endl;
+  std::cout << "Height: " << h << std::endl;
+  std::cout << "Num pixels: " << w * h << std::endl;
+
+  if(w > 0 && h > 0)
+  {
+    std::cout << "Top left pixel color:"
+              << " r: " << (int)image[0]
+              << " g: " << (int)image[1]
+              << " b: " << (int)image[2]
+              << " a: " << (int)image[3]
+              << std::endl;
+  }
+
+
+  displayPNGInfo(state.info_png);
+  std::cout << std::endl;
+  displayChunkNames(buffer);
+  std::cout << std::endl;
+  displayFilterTypes(buffer, ignore_checksums);
+  std::cout << std::endl;
+  displayAsciiArt(image, w, h);
+}
diff --git a/examples/example_reencode.cpp b/examples/example_reencode.cpp
new file mode 100644
index 0000000..d438612
--- /dev/null
+++ b/examples/example_reencode.cpp
@@ -0,0 +1,76 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2010 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+/*
+LodePNG decode-encode: decodes the image, then encodes it again, with all the
+same information, chunks, color types, etc... as the original image had.
+This sample shows how LodePNG can be used for a conforming PNG editor.
+*/
+
+//g++ lodepng.cpp example_reencode.cpp -ansi -pedantic -Wall -Wextra -lSDL -O3 -o reencode
+
+#include "lodepng.h"
+
+#include <iostream>
+
+int main(int argc, char *argv[])
+{
+  std::vector<unsigned char> image;
+  unsigned w, h;
+  std::vector<unsigned char> buffer;
+  lodepng::State state;
+  unsigned error;
+  
+  //check if user gave a filename
+  if(argc < 3)
+  {
+    std::cout << "please provide in and out filename" << std::endl;
+    return 0;
+  }
+  
+  state.decoder.color_convert = 0;
+  state.decoder.remember_unknown_chunks = 1; //make it reproduce even unknown chunks in the saved image
+  
+  lodepng::load_file(buffer, argv[1]);
+  error = lodepng::decode(image, w, h, state, buffer);
+  if(error)
+  {
+    std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+  
+  buffer.clear();
+  
+  state.encoder.text_compression = 1;
+  
+  error = lodepng::encode(buffer, image, w, h, state);
+  if(error)
+  {
+    std::cout << "encoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+  
+  lodepng::save_file(buffer, argv[2]);
+}
diff --git a/examples/example_sdl.c b/examples/example_sdl.c
new file mode 100644
index 0000000..e4ae3de
--- /dev/null
+++ b/examples/example_sdl.c
@@ -0,0 +1,142 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+/*
+Compile command for Linux:
+gcc lodepng.c example_sdl.c -ansi -pedantic -Wall -Wextra -lSDL -O3 -o showpng
+
+*/
+
+/*
+LodePNG SDL example
+This example displays a PNG with a checkerboard pattern to show tranparency.
+It requires the SDL library to compile and run.
+If multiple filenames are given to the command line, it shows all of them.
+Press any key to see next image, or esc to quit.
+*/
+
+#include "lodepng.h"
+
+#include <SDL/SDL.h>
+
+/*shows image with SDL. Returns 1 if user wants to fully quit, 0 if user wants to see next image.*/
+int show(const char* filename)
+{
+  unsigned error;
+  unsigned char* image;
+  unsigned w, h, x, y;
+  SDL_Surface* scr;
+  SDL_Event event;
+  int done;
+  size_t jump = 1;
+
+  printf("showing %s\n", filename);
+
+  /*load the PNG in one function call*/
+  error = lodepng_decode32_file(&image, &w, &h, filename);
+
+  /*stop if there is an error*/
+  if(error)
+  {
+    printf("decoder error %u: %s\n", error, lodepng_error_text(error));
+    return 0;
+  }
+
+  /*avoid too large window size by downscaling large image*/
+
+  if(w / 1024 >= jump) jump = w / 1024 + 1;
+  if(h / 1024 >= jump) jump = h / 1024 + 1;
+
+  /*init SDL*/
+  if(SDL_Init(SDL_INIT_VIDEO) < 0)
+  {
+    printf("Error, SDL video init failed\n");
+    return 0;
+  }
+  scr = SDL_SetVideoMode(w / jump, h / jump, 32, SDL_HWSURFACE);
+  if(!scr)
+  {
+    printf("Error, no SDL screen\n");
+    return 0;
+  }
+  SDL_WM_SetCaption(filename, NULL); /*set window caption*/
+
+  /*plot the pixels of the PNG file*/
+  for(y = 0; y + jump - 1 < h; y += jump)
+  for(x = 0; x + jump - 1 < w; x += jump)
+  {
+    int checkerColor;
+    Uint32* bufp;
+    Uint32 r, g, b, a;
+
+    /*get RGBA components*/
+    r = image[4 * y * w + 4 * x + 0]; /*red*/
+    g = image[4 * y * w + 4 * x + 1]; /*green*/
+    b = image[4 * y * w + 4 * x + 2]; /*blue*/
+    a = image[4 * y * w + 4 * x + 3]; /*alpha*/
+
+    /*make translucency visible by placing checkerboard pattern behind image*/
+    checkerColor = 191 + 64 * (((x / 16) % 2) == ((y / 16) % 2));
+    r = (a * r + (255 - a) * checkerColor) / 255;
+    g = (a * g + (255 - a) * checkerColor) / 255;
+    b = (a * b + (255 - a) * checkerColor) / 255;
+
+    /*give the color value to the pixel of the screenbuffer*/
+    bufp = (Uint32 *)scr->pixels + (y * scr->pitch / 4) / jump + (x / jump);
+    *bufp = 65536 * r + 256 * g + b;
+  }
+
+  /*pause until you press escape and meanwhile redraw screen*/
+  done = 0;
+  while(done == 0)
+  {
+    while(SDL_PollEvent(&event))
+    {
+      if(event.type == SDL_QUIT) done = 2;
+      else if(SDL_GetKeyState(NULL)[SDLK_ESCAPE]) done = 2;
+      else if(event.type == SDL_KEYDOWN) done = 1; /*press any other key for next image*/
+    }
+    SDL_UpdateRect(scr, 0, 0, 0, 0); /*redraw screen*/
+    SDL_Delay(5); /*pause 5 ms so it consumes less processing power*/
+  }
+
+  /*cleanup*/
+  free(image);
+  SDL_Quit();
+  return done == 2 ? 1 : 0;
+}
+
+int main(int argc, char* argv[])
+{
+  int i;
+
+  if(argc <= 1) printf("Please enter PNG file name(s) to display\n");;
+
+  for(i = 1; i < argc; i++)
+  {
+    if(show(argv[i])) return 0;
+  }
+  return 0;
+}
diff --git a/examples/example_sdl.cpp b/examples/example_sdl.cpp
new file mode 100644
index 0000000..0c68ef5
--- /dev/null
+++ b/examples/example_sdl.cpp
@@ -0,0 +1,132 @@
+/*
+LodePNG Examples
+
+Copyright (c) 2005-2012 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software
+    in a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
+//Compile command for Linux:
+//g++ lodepng.cpp example_sdl.cpp -lSDL -O3 -o showpng
+
+/*
+LodePNG SDL example
+This example displays a PNG with a checkerboard pattern to show tranparency.
+It requires the SDL library to compile and run.
+If multiple filenames are given to the command line, it shows all of them.
+Press any key to see next image, or esc to quit.
+*/
+
+#include "lodepng.h"
+
+#include <iostream>
+#include <SDL/SDL.h>
+
+int show(const std::string& caption, const unsigned char* rgba, unsigned w, unsigned h)
+{
+  //avoid too large window size by downscaling large image
+  unsigned jump = 1;
+  if(w / 1024 >= jump) jump = w / 1024 + 1;
+  if(h / 1024 >= jump) jump = h / 1024 + 1;
+
+  //init SDL
+  if(SDL_Init(SDL_INIT_VIDEO) < 0)
+  {
+    std::cout << "error, SDL video init failed" << std::endl;
+    return 0;
+  }
+  SDL_Surface* scr = SDL_SetVideoMode(w / jump, h / jump, 32, SDL_HWSURFACE);
+  if(!scr)
+  {
+    std::cout << "error, no SDL screen" << std::endl;
+    return 0;
+  }
+  SDL_WM_SetCaption(caption.c_str(), NULL); //set window caption
+
+  //plot the pixels of the PNG file
+  for(unsigned y = 0; y + jump - 1 < h; y += jump)
+  for(unsigned x = 0; x + jump - 1 < w; x += jump)
+  {
+    //get RGBA components
+    Uint32 r = rgba[4 * y * w + 4 * x + 0]; //red
+    Uint32 g = rgba[4 * y * w + 4 * x + 1]; //green
+    Uint32 b = rgba[4 * y * w + 4 * x + 2]; //blue
+    Uint32 a = rgba[4 * y * w + 4 * x + 3]; //alpha
+
+    //make translucency visible by placing checkerboard pattern behind image
+    int checkerColor = 191 + 64 * (((x / 16) % 2) == ((y / 16) % 2));
+    r = (a * r + (255 - a) * checkerColor) / 255;
+    g = (a * g + (255 - a) * checkerColor) / 255;
+    b = (a * b + (255 - a) * checkerColor) / 255;
+
+    //give the color value to the pixel of the screenbuffer
+    Uint32* bufp;
+    bufp = (Uint32 *)scr->pixels + (y * scr->pitch / 4) / jump + (x / jump);
+    *bufp = 65536 * r + 256 * g + b;
+  }
+
+  //pause until you press escape and meanwhile redraw screen
+  SDL_Event event;
+  int done = 0;
+  while(done == 0)
+  {
+    while(SDL_PollEvent(&event))
+    {
+      if(event.type == SDL_QUIT) done = 2;
+      else if(SDL_GetKeyState(NULL)[SDLK_ESCAPE]) done = 2;
+      else if(event.type == SDL_KEYDOWN) done = 1; //press any other key for next image
+    }
+    SDL_UpdateRect(scr, 0, 0, 0, 0); //redraw screen
+    SDL_Delay(5); //pause 5 ms so it consumes less processing power
+  }
+
+  SDL_Quit();
+  return done == 2 ? 1 : 0;
+}
+
+/*shows image with SDL. Returns 1 if user wants to fully quit, 0 if user wants to see next image.*/
+int showfile(const char* filename)
+{
+  std::cout << "showing " << filename << std::endl;
+
+  std::vector<unsigned char> buffer, image;
+  lodepng::load_file(buffer, filename); //load the image file with given filename
+  unsigned w, h;
+  unsigned error = lodepng::decode(image, w, h, buffer); //decode the png
+
+  //stop if there is an error
+  if(error)
+  {
+    std::cout << "decoder error " << error << ": " << lodepng_error_text(error) << std::endl;
+    return 0;
+  }
+
+  return show(filename, &image[0], w, h);
+}
+
+int main(int argc, char* argv[])
+{
+  if(argc <= 1) std::cout << "Please enter PNG file name(s) to display" << std::endl;
+
+  for(int i = 1; i < argc; i++)
+  {
+    if(showfile(argv[i])) return 0;
+  }
+}