From 8e5b1e0b171d0e4ff326a3ff1af162805d82a3d6 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Sat, 2 May 2020 13:16:18 +0200
Subject: Add support for 90 dgr. rotated text rendering.

---
 plugingui/painter.cc | 48 +++++++++++++++++++++++++++++++++++++++++++++---
 plugingui/painter.h  |  2 +-
 2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/plugingui/painter.cc b/plugingui/painter.cc
index bad5318..f2fc66a 100644
--- a/plugingui/painter.cc
+++ b/plugingui/painter.cc
@@ -175,11 +175,14 @@ void Painter::clear()
 }
 
 void Painter::drawText(int x0, int y0, const Font& font,
-                       const std::string& text, bool nocolour)
+                       const std::string& text, bool nocolour, bool rotate)
 {
 	PixelBufferAlpha* textbuf = font.render(text);
 
-	y0 -= textbuf->height; // The y0 offset (baseline) is the bottom of the text.
+	if(!rotate)
+	{
+		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))
@@ -222,6 +225,42 @@ void Painter::drawText(int x0, int y0, const Font& font,
 			pixbuf.blendLine(x + x0, y + y0, c, renderWidth - x);
 		}
 	}
+	else if(rotate)
+	{
+		int renderWidth = textbuf->height;
+		if(renderWidth > (int)(pixbuf.width - x0))
+		{
+			renderWidth = pixbuf.width - x0;
+		}
+
+		int renderHeight = textbuf->width;
+		if(renderHeight > ((int)pixbuf.height - y0))
+		{
+			renderHeight = ((int)pixbuf.height - y0);
+		}
+
+		for(int y = -1 * std::min(0, y0); y < renderHeight; ++y)
+		{
+			for(int x = -1 * std::min(0, x0); x < renderWidth; ++x)
+			{
+				assert(x >= 0);
+				assert(y >= 0);
+				assert(x < (int)textbuf->height);
+				assert(y < (int)textbuf->width);
+
+				auto c = textbuf->pixel(textbuf->width - y - 1, x);
+
+				assert(x + x0 >= 0);
+				assert(y + y0 >= 0);
+				assert(x + x0 < (int)pixbuf.width);
+				assert(y + y0 < (int)pixbuf.height);
+
+				Colour col(colour.red(), colour.green(),
+				           colour.blue(), (int)(colour.alpha() * c.alpha()) / 255);
+				pixbuf.addPixel(x + x0, y + y0, col);
+			}
+		}
+	}
 	else
 	{
 		for(int y = -1 * std::min(0, y0); y < renderHeight; ++y)
@@ -252,7 +291,10 @@ void Painter::drawText(int x0, int y0, const Font& font,
 
 void Painter::drawPoint(int x, int y)
 {
-	pixbuf.setPixel(x, y, colour);
+	if(x >= 0 && y >= 0 && (std::size_t)x < pixbuf.width && (std::size_t)y < pixbuf.height)
+	{
+		pixbuf.setPixel(x, y, colour);
+	}
 }
 
 static void plot4points(Painter *p, int cx, int cy, int x, int y)
diff --git a/plugingui/painter.h b/plugingui/painter.h
index b38bf88..9bf7fbf 100644
--- a/plugingui/painter.h
+++ b/plugingui/painter.h
@@ -49,7 +49,7 @@ public:
 
 	void drawLine(int x1, int y1, int x2, int y2);
 	void drawText(int x, int y, const Font& font, const std::string& text,
-	              bool nocolour = false);
+	              bool nocolour = false, bool rotate = false);
 	void drawRectangle(int x1, int y1, int x2, int y2);
 	void drawFilledRectangle(int x1, int y1, int x2, int y2);
 	void drawPoint(int x, int y);
-- 
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