Add Canvas base class for the Painter to draw on. This is done in preparation for a new Painter unittest.

6 files changed, 151 insertions, 71 deletions

diff --git a/plugingui/canvas.h b/plugingui/canvas.h
new file mode 100644
index 0000000..8cfe083
--- /dev/null
+++ b/plugingui/canvas.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ *            canvas.h
+ *
+ *  Sun Sep  4 13:03:51 CEST 2016
+ *  Copyright 2016 Bent Bisballe Nyeng
+ *  deva@aasimon.org
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include "pixelbuffer.h"
+
+namespace GUI
+{
+
+//! Abstract class that can be used by the Paiter to draw on.
+class Canvas
+{
+public:
+	//! @returns a reference to the pixel buffer.
+	virtual PixelBufferAlpha& GetPixelBuffer() = 0;
+
+	//! Signal the beginning of a paint operation.
+	virtual void beginPaint() = 0;
+
+	//! Signal the ending of a paint operation
+	//! This might trigger a redraw operation.
+	virtual void endPaint() = 0;
+
+};
+
+} // GUI::
diff --git a/plugingui/painter.cc b/plugingui/painter.cc
index 7d55294..db67a0e 100644
--- a/plugingui/painter.cc
+++ b/plugingui/painter.cc
@@ -26,32 +26,22 @@
  */
 #include "painter.h"
 
-#include "window.h"
-
 #include <cmath>
 
 namespace GUI
 {
 
-Painter::Painter(Widget& widget)
-	: widget(widget)
+Painter::Painter(Canvas& canvas)
+	: canvas(canvas)
+	, pixbuf(canvas.GetPixelBuffer())
 {
-	if(widget.window())
-	{
-		widget.window()->beginPaint();
-	}
-
-	pixbuf = &widget.pixbuf;
+	canvas.beginPaint();
 	colour = Colour(0.0f, 0.0f, 0.0f, 0.5f);
 }
 
 Painter::~Painter()
 {
-	if(widget.window())
-	{
-		widget.window()->endPaint();
-	}
-
+	canvas.endPaint();
 	flush();
 }
 
@@ -60,20 +50,20 @@ void Painter::setColour(const Colour& colour)
 	this->colour = colour;
 }
 
-static void plot(PixelBufferAlpha* pixbuf, const Colour& colour,
+static void plot(PixelBufferAlpha& pixbuf, const Colour& colour,
                  int x, int y, double c)
 {
-	if((x >= (int)pixbuf->width) || (y >= (int)pixbuf->height))
+	if((x >= (int)pixbuf.width) || (y >= (int)pixbuf.height))
 	{
 		return;
 	}
 
 	// plot the pixel at (x, y) with brightness c (where 0 ≤ c ≤ 1)
-	pixbuf->addPixel(x, y,
-	                 (unsigned char)(colour.red() * 255.0),
-	                 (unsigned char)(colour.green() * 255.0),
-	                 (unsigned char)(colour.blue() * 255.0),
-	                 (unsigned char)(colour.alpha() * 255 * c));
+	pixbuf.addPixel(x, y,
+	                (unsigned char)(colour.red() * 255.0),
+	                (unsigned char)(colour.green() * 255.0),
+	                (unsigned char)(colour.blue() * 255.0),
+	                (unsigned char)(colour.alpha() * 255 * c));
 
 }
 
@@ -175,11 +165,11 @@ void Painter::drawFilledRectangle(int x1, int y1, int x2, int y2)
 
 void Painter::clear()
 {
-	for(int x = 0; x < (int)pixbuf->width; ++x)
+	for(int x = 0; x < (int)pixbuf.width; ++x)
 	{
-		for(int y = 0; y < (int)pixbuf->height; ++y)
+		for(int y = 0; y < (int)pixbuf.height; ++y)
 		{
-			pixbuf->setPixel(x, y, 0, 0, 0, 0);
+			pixbuf.setPixel(x, y, 0, 0, 0, 0);
 		}
 	}
 }
@@ -192,7 +182,7 @@ void Painter::drawText(int x0, int y0, const Font& font,
 	y0 -= textbuf->height; // The y0 offset (baseline) is the bottom of the text.
 
 	// If the text offset is outside the buffer; skip it.
-	if((x0 > (int)pixbuf->width) || (y0 > (int)pixbuf->height))
+	if((x0 > (int)pixbuf.width) || (y0 > (int)pixbuf.height))
 	{
 		delete textbuf;
 		return;
@@ -200,15 +190,15 @@ void Painter::drawText(int x0, int y0, const Font& font,
 
 	// Make sure we don't try to draw outside the pixbuf.
 	int renderWidth = textbuf->width;
-	if(renderWidth > (int)(pixbuf->width - x0))
+	if(renderWidth > (int)(pixbuf.width - x0))
 	{
-		renderWidth = pixbuf->width - x0;
+		renderWidth = pixbuf.width - x0;
 	}
 
 	int renderHeight = textbuf->height;
-	if(renderHeight > ((int)pixbuf->height - y0))
+	if(renderHeight > ((int)pixbuf.height - y0))
 	{
-		renderHeight = ((int)pixbuf->height - y0);
+		renderHeight = ((int)pixbuf.height - y0);
 	}
 
 	if(nocolour)
@@ -219,7 +209,7 @@ void Painter::drawText(int x0, int y0, const Font& font,
 			{
 				unsigned char r, g, b, a;
 				textbuf->pixel(x, y, &r, &g, &b, &a);
-				pixbuf->addPixel(x + x0, y + y0, r, g, b, a);
+				pixbuf.addPixel(x + x0, y + y0, r, g, b, a);
 			}
 		}
 	}
@@ -231,11 +221,11 @@ void Painter::drawText(int x0, int y0, const Font& font,
 			{
 				unsigned char r,g,b,a;
 				textbuf->pixel(x, y, &r, &g, &b, &a);
-				pixbuf->addPixel(x + x0, y + y0,
-				                 colour.red() * 255,
-				                 colour.green() * 255,
-				                 colour.blue() * 255,
-				                 colour.alpha() * a);
+				pixbuf.addPixel(x + x0, y + y0,
+				                colour.red() * 255,
+				                colour.green() * 255,
+				                colour.blue() * 255,
+				                colour.alpha() * a);
 			}
 		}
 	}
@@ -245,11 +235,11 @@ void Painter::drawText(int x0, int y0, const Font& font,
 
 void Painter::drawPoint(int x, int y)
 {
-	pixbuf->setPixel(x, y,
-	                 (unsigned char)(colour.red() * 255.0),
-	                 (unsigned char)(colour.green() * 255.0),
-	                 (unsigned char)(colour.blue() * 255.0),
-	                 (unsigned char)(colour.alpha() * 255.0));
+	pixbuf.setPixel(x, y,
+	                (unsigned char)(colour.red() * 255.0),
+	                (unsigned char)(colour.green() * 255.0),
+	                (unsigned char)(colour.blue() * 255.0),
+	                (unsigned char)(colour.alpha() * 255.0));
 }
 
 static void plot4points(Painter *p, int cx, int cy, int x, int y)
@@ -348,26 +338,31 @@ void Painter::drawFilledCircle(int cx, int cy, int radius)
 
 void Painter::drawImage(int x0, int y0, const Drawable& image)
 {
-	size_t fw = image.width();
-	size_t fh = image.height();
+	int fw = image.width();
+	int fh = image.height();
 
 	// Make sure we don't try to draw outside the pixbuf.
-	if(fw > (pixbuf->width - x0))
+	if(fw > (int)(pixbuf.width - x0))
 	{
-		fw = (pixbuf->width - x0);
+		fw = (int)(pixbuf.width - x0);
 	}
 
-	if(fh > (pixbuf->height - y0))
+	if(fh > (int)(pixbuf.height - y0))
 	{
-		fh = (pixbuf->height - y0);
+		fh = (int)(pixbuf.height - y0);
+	}
+
+	if((fw < 1) || (fh < 1))
+	{
+		return;
 	}
 
-	for(size_t y = 0; y < fh; ++y)
+	for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
 	{
-		for(size_t x = 0; x < fw; ++x)
+		for(std::size_t x = -1 * std::min(0, x0); x < (std::size_t)fw; ++x)
 		{
 			auto& c = image.getPixel(x, y);
-			pixbuf->addPixel(x0 + x, y0 + y, c);
+			pixbuf.addPixel(x0 + x, y0 + y, c);
 		}
 	}
 }
@@ -375,33 +370,33 @@ void Painter::drawImage(int x0, int y0, const Drawable& image)
 void Painter::drawImageStretched(int x0, int y0, const Drawable& image,
                                  int width, int height)
 {
-	if((width < 1) || (height < 1))
-	{
-		return;
-	}
-
 	float fw = image.width();
 	float fh = image.height();
 
 	// Make sure we don't try to draw outside the pixbuf.
-	if(width > (int)(pixbuf->width - x0))
+	if(width > (int)(pixbuf.width - x0))
 	{
-		width = pixbuf->width - x0;
+		width = pixbuf.width - x0;
 	}
 
-	if(height > (int)(pixbuf->height - y0))
+	if(height > (int)(pixbuf.height - y0))
 	{
-		height = pixbuf->height - y0;
+		height = pixbuf.height - y0;
+	}
+
+	if((width < 1) || (height < 1))
+	{
+		return;
 	}
 
-	for(int y = 0; y < height; ++y)
+	for(int y = -1 * std::min(0, y0); y < height; ++y)
 	{
-		for(int x = 0; x < width; ++x)
+		for(int x = -1 * std::min(0, x0); x < width; ++x)
 		{
 			int lx = ((float)x / (float)width) * fw;
 			int ly = ((float)y / (float)height) * fh;
 			auto& c = image.getPixel(lx, ly);
-			pixbuf->addPixel(x0 + x, y0 + y, c);
+			pixbuf.addPixel(x0 + x, y0 + y, c);
 		}
 	}
 }
diff --git a/plugingui/painter.h b/plugingui/painter.h
index 233d157..7e1fede 100644
--- a/plugingui/painter.h
+++ b/plugingui/painter.h
@@ -42,7 +42,7 @@ namespace GUI
 class Painter
 {
 public:
-	Painter(Widget& widget);
+	Painter(Canvas& canvas);
 	~Painter();
 
 	void flush();
@@ -84,8 +84,8 @@ public:
 	void clear();
 
 private:
-	Widget& widget;
-	PixelBufferAlpha* pixbuf;
+	Canvas& canvas;
+	PixelBufferAlpha& pixbuf;
 	Colour colour;
 };
 
diff --git a/plugingui/widget.cc b/plugingui/widget.cc
index 5cd013d..3d9d47c 100644
--- a/plugingui/widget.cc
+++ b/plugingui/widget.cc
@@ -133,6 +133,27 @@ size_t Widget::height()
 	return _height;
 }
 
+PixelBufferAlpha& Widget::GetPixelBuffer()
+{
+	return pixbuf;
+}
+
+void Widget::beginPaint()
+{
+	if(_window)
+	{
+		_window->beginPaint();
+	}
+}
+
+void Widget::endPaint()
+{
+	if(_window)
+	{
+		_window->endPaint();
+	}
+}
+
 size_t Widget::windowX()
 {
 	size_t window_x = x();
diff --git a/plugingui/widget.h b/plugingui/widget.h
index bbe85d0..26070c5 100644
--- a/plugingui/widget.h
+++ b/plugingui/widget.h
@@ -30,15 +30,21 @@
 #include "pixelbuffer.h"
 #include "notifier.h"
 #include "layout.h"
+#include "canvas.h"
 
 #include <vector>
 
-namespace GUI {
+namespace GUI
+{
 
 class ImageCache;
 class Window;
 
-class Widget : public Listener, public LayoutItem {
+class Widget
+	: public Listener
+	, public LayoutItem
+	, public Canvas
+{
 	friend class Painter;
 public:
 	Widget(Widget* parent);
@@ -55,6 +61,11 @@ public:
 	virtual size_t width() override;
 	virtual size_t height() override;
 
+	// From Canvas
+	PixelBufferAlpha& GetPixelBuffer() override;
+	void beginPaint() override;
+	void endPaint() override;
+
 	virtual size_t windowX();
 	virtual size_t windowY();
 
diff --git a/plugingui/window.h b/plugingui/window.h
index 9eb9d6d..8b186e9 100644
--- a/plugingui/window.h
+++ b/plugingui/window.h
@@ -34,11 +34,14 @@
 #include "eventhandler.h"
 #include "imagecache.h"
 
-namespace GUI {
+namespace GUI
+{
 
-class Window : public Widget {
+class Window
+	: public Widget
+{
 public:
-	Window(void* native_window);
+	Window(void* native_window = nullptr);
 	~Window();
 
 	void setFixedSize(int width, int height);
@@ -74,7 +77,7 @@ protected:
 	void updateBuffer();
 
 	// For the Painter
-	friend class Painter;
+	friend class Widget;
 	void beginPaint();
 	void endPaint();