WIP: Read images as uint8_t instead of float. Convert Colour and all colour related operations to use uint8_t instade of float and finally optimize rendering to render lines instead of single pixels.

14 files changed, 422 insertions, 151 deletions

diff --git a/plugingui/colour.cc b/plugingui/colour.cc
index 02d03c6..7fd649c 100644
--- a/plugingui/colour.cc
+++ b/plugingui/colour.cc
@@ -28,43 +28,50 @@
 
 #include <cstring>
 
-namespace GUI {
+namespace GUI
+{
 
 Colour::Colour()
 {
-	data = {{1.0f, 1.0f, 1.0f, 1.0f}};
 }
 
 Colour::Colour(float grey, float a)
+	: pixel({{(std::uint8_t)(grey * 255),
+	          (std::uint8_t)(grey * 255),
+	          (std::uint8_t)(grey * 255),
+	          (std::uint8_t)(a * 255)}})
 {
-	data = {{grey, grey, grey, a}};
 }
 
 Colour::Colour(float r, float g, float b, float a)
+	: pixel({{(std::uint8_t)(r * 255),
+	          (std::uint8_t)(g * 255),
+	          (std::uint8_t)(b * 255),
+	          (std::uint8_t)(a * 255)}})
 {
-	data = {{r, g, b, a}};
 }
 
 Colour::Colour(std::uint8_t r, std::uint8_t g, std::uint8_t b, std::uint8_t a)
-	: Colour(r / 255.0f, g / 255.0f, b / 255.0f, a / 255.0f)
-{}
+	: pixel({{r, g, b, a}})
+{
+}
 
 Colour::Colour(const Colour& other)
+	: pixel(other.pixel)
 {
-	data = other.data;
 }
 
 Colour& Colour::operator=(const Colour& other)
 {
-	data = other.data;
+	pixel = other.pixel;
 	return *this;
 }
 
 bool Colour::operator==(const Colour& other) const
 {
-	return data[0] == other.data[0] &&
-	       data[1] == other.data[1] &&
-	       data[2] == other.data[2];
+	return pixel[0] == other.pixel[0] &&
+	       pixel[1] == other.pixel[1] &&
+	       pixel[2] == other.pixel[2];
 }
 
 bool Colour::operator!=(const Colour& other) const
diff --git a/plugingui/colour.h b/plugingui/colour.h
index 3a135fc..0bc8659 100644
--- a/plugingui/colour.h
+++ b/plugingui/colour.h
@@ -32,7 +32,8 @@
 namespace GUI
 {
 
-class Colour {
+class Colour
+{
 public:
 	Colour();
 	Colour(float grey, float alpha = 1.0f);
@@ -45,13 +46,16 @@ public:
 	bool operator==(const Colour& other) const;
 	bool operator!=(const Colour& other) const;
 
-	inline float red() const { return data[0]; }
-	inline float green() const { return data[1]; }
-	inline float blue() const { return data[2]; }
-	inline float alpha() const { return data[3]; }
+	inline std::uint8_t red() const { return pixel[0]; }
+	inline std::uint8_t green() const { return pixel[1]; }
+	inline std::uint8_t blue() const { return pixel[2]; }
+	inline std::uint8_t alpha() const { return pixel[3]; }
+
+	std::uint8_t* data() { return pixel.data(); }
+	const std::uint8_t* data() const { return pixel.data(); }
 
 private:
-	std::array<float, 4> data;
+	std::array<std::uint8_t, 4> pixel{{255, 255, 255, 255}};
 };
 
 } // GUI::
diff --git a/plugingui/drawable.h b/plugingui/drawable.h
index ff9a4ff..e793a27 100644
--- a/plugingui/drawable.h
+++ b/plugingui/drawable.h
@@ -27,6 +27,7 @@
 #pragma once
 
 #include <cstdlib>
+#include <cstdint>
 
 namespace GUI
 {
@@ -42,6 +43,9 @@ public:
 	virtual std::size_t height() const = 0;
 
 	virtual const Colour& getPixel(std::size_t x, std::size_t y) const = 0;
+	virtual const std::uint8_t* line(std::size_t y) const = 0;
+
+	virtual bool hasAlpha() const = 0;
 };
 
 } // GUI::
diff --git a/plugingui/font.cc b/plugingui/font.cc
index 9f54b16..0500e81 100644
--- a/plugingui/font.cc
+++ b/plugingui/font.cc
@@ -59,8 +59,8 @@ Font::Font(const std::string& fontfile)
 			auto& pixel = img_font.getPixel(px, 0);
 
 			// Find next purple pixel in top row:
-			if((pixel.red() == 1.0f) && (pixel.green() == 0.0f) &&
-			   (pixel.blue() == 1.0f) && (pixel.alpha() == 1.0f))
+			if((pixel.red() == 255) && (pixel.green() == 0) &&
+			   (pixel.blue() == 255) && (pixel.alpha() == 255))
 			{
 				break;
 			}
@@ -124,9 +124,7 @@ PixelBufferAlpha *Font::render(const std::string& text) const
 			for(size_t y = 0; y < img_font.height(); ++y)
 			{
 				auto& c = img_font.getPixel(x + character.offset, y);
-				pb->setPixel(x + x_offset + character.pre_bias, y,
-				             c.red() * 255, c.green() * 255,
-				             c.blue() * 255, c.alpha() * 255);
+				pb->setPixel(x + x_offset + character.pre_bias, y, c);
 			}
 		}
 		x_offset += character.width + spacing + character.post_bias;
diff --git a/plugingui/image.cc b/plugingui/image.cc
index 70ee08e..54fd15e 100644
--- a/plugingui/image.cc
+++ b/plugingui/image.cc
@@ -60,6 +60,7 @@ Image::Image(Image&& other)
 	: _width(other._width)
 	, _height(other._height)
 	, image_data(std::move(other.image_data))
+	, image_data_raw(std::move(other.image_data_raw))
 	, filename(other.filename)
 {
 	other._width = 0;
@@ -74,6 +75,8 @@ Image& Image::operator=(Image&& other)
 {
 	image_data.clear();
 	image_data = std::move(other.image_data);
+	image_data_raw.clear();
+	image_data_raw = std::move(other.image_data_raw);
 	_width = other._width;
 	_height = other._height;
 	valid = other.valid;
@@ -111,6 +114,10 @@ void Image::setError()
 	image_data.clear();
 	image_data.reserve(_width * _height);
 
+	image_data_raw.clear();
+	image_data_raw.reserve(_width * _height * 4);
+	memcpy(image_data_raw.data(), ptr, _height * _width);
+
 	for(std::size_t y = 0; y < _height; ++y)
 	{
 		for(std::size_t x = 0; x < _width; ++x)
@@ -125,6 +132,7 @@ void Image::setError()
 
 void Image::load(const char* data, size_t size)
 {
+	has_alpha = false;
 	unsigned int iw{0}, ih{0};
 	std::uint8_t* char_image_data{nullptr};
 	unsigned int res = lodepng_decode32((std::uint8_t**)&char_image_data,
@@ -145,12 +153,17 @@ void Image::load(const char* data, size_t size)
 	image_data.clear();
 	image_data.reserve(_width * _height);
 
+	image_data_raw.clear();
+	image_data_raw.reserve(_width * _height * 4);
+	memcpy(image_data_raw.data(), char_image_data, _height * _width * 4);
+
 	for(std::size_t y = 0; y < _height; ++y)
 	{
 		for(std::size_t x = 0; x < _width; ++x)
 		{
 			std::uint8_t* ptr = &char_image_data[(x + y * _width) * 4];
 			image_data.emplace_back(Colour{ptr[0], ptr[1], ptr[2], ptr[3]});
+			has_alpha |= ptr[3] != 0xff;
 		}
 	}
 
@@ -180,6 +193,16 @@ const Colour& Image::getPixel(size_t x, size_t y) const
 	return image_data[x + y * _width];
 }
 
+const std::uint8_t* Image::line(std::size_t y) const
+{
+	return image_data_raw.data() + y * _width * 4;
+}
+
+bool Image::hasAlpha() const
+{
+	return has_alpha;
+}
+
 bool Image::isValid() const
 {
 	return valid;
diff --git a/plugingui/image.h b/plugingui/image.h
index dd7f347..4d140ab 100644
--- a/plugingui/image.h
+++ b/plugingui/image.h
@@ -50,6 +50,9 @@ public:
 	size_t height() const override;
 
 	const Colour& getPixel(size_t x, size_t y) const override;
+	const std::uint8_t* line(std::size_t y) const override;
+
+	bool hasAlpha() const override;
 
 	bool isValid() const;
 
@@ -62,8 +65,10 @@ private:
 	std::size_t _width{0};
 	std::size_t _height{0};
 	std::vector<Colour> image_data;
+	std::vector<std::uint8_t> image_data_raw;
 	Colour out_of_range{0.0f, 0.0f, 0.0f, 0.0f};
 	std::string filename;
+	bool has_alpha{false};
 };
 
 } // GUI::
diff --git a/plugingui/painter.cc b/plugingui/painter.cc
index acc92cb..89d7498 100644
--- a/plugingui/painter.cc
+++ b/plugingui/painter.cc
@@ -65,12 +65,7 @@ static void plot(PixelBufferAlpha& pixbuf, const Colour& colour,
 	}
 
 	// 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, colour.red(), colour.green(), colour.blue(), colour.alpha() * c);
 }
 
 static inline double fpart(double x)
@@ -171,13 +166,7 @@ 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 y = 0; y < (int)pixbuf.height; ++y)
-		{
-			pixbuf.setPixel(x, y, 0, 0, 0, 0);
-		}
-	}
+	pixbuf.clear();
 }
 
 void Painter::drawText(int x0, int y0, const Font& font,
@@ -251,11 +240,8 @@ void Painter::drawText(int x0, int y0, const Font& font,
 				assert(x + x0 < (int)pixbuf.width);
 				assert(y + y0 < (int)pixbuf.height);
 
-				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(), colour.green(),
+				                colour.blue(), (int)(colour.alpha() * a) / 255);
 			}
 		}
 	}
@@ -265,11 +251,7 @@ 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, colour);
 }
 
 static void plot4points(Painter *p, int cx, int cy, int x, int y)
@@ -387,28 +369,123 @@ void Painter::drawImage(int x0, int y0, const Drawable& image)
 		return;
 	}
 
-	for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
+	if(image.hasAlpha())
 	{
-		for(std::size_t x = -1 * std::min(0, x0); x < (std::size_t)fw; ++x)
+		if(true || !image.line(0))
+		{
+			for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
+			{
+				for(std::size_t x = -1 * std::min(0, x0); x < (std::size_t)fw; ++x)
+				{
+					assert(x >= 0);
+					assert(y >= 0);
+					assert(x < image.width());
+					assert(y < image.height());
+					auto& c = image.getPixel(x, y);
+
+					assert(x0 + x >= 0);
+					assert(y0 + y >= 0);
+					assert(x0 + x < pixbuf.width);
+					assert(y0 + y < pixbuf.height);
+
+					if (!has_restriction || c == restriction_colour)
+					{
+						pixbuf.addPixel(x0 + x, y0 + y, c);
+					}
+				}
+			}
+		}
+		else
 		{
-			assert(x >= 0);
-			assert(y >= 0);
-			assert(x < image.width());
-			assert(y < image.height());
-			auto& c = image.getPixel(x, y);
-
-			assert(x0 + x >= 0);
-			assert(y0 + y >= 0);
-			assert(x0 + x < pixbuf.width);
-			assert(y0 + y < pixbuf.height);
-
-			if (!has_restriction || c == restriction_colour)
+			std::size_t x = -1 * std::min(0, x0);
+			for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
 			{
-				pixbuf.addPixel(x0 + x, y0 + y, c);
+				pixbuf.blendLine(x + x0, y + y0, image.line(y), image.width());
+			}
+		}
+	}
+	else
+	{
+		std::size_t x = -1 * std::min(0, x0);
+		for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
+		{
+			pixbuf.writeLine(x + x0, y + y0, image.line(y), image.width());
+		}
+	}
+}
+
+#if 0
+void Painter::drawImage(int x0, int y0, const Drawable& image)
+{
+	int fw = image.width();
+	int fh = image.height();
+
+	// Make sure we don't try to draw outside the pixbuf.
+	if(fw > (int)(pixbuf.width - x0))
+	{
+		fw = (int)(pixbuf.width - x0);
+	}
+
+	if(fh > (int)(pixbuf.height - y0))
+	{
+		fh = (int)(pixbuf.height - y0);
+	}
+
+	if((fw < 1) || (fh < 1))
+	{
+		return;
+	}
+
+	if(image.hasAlpha())
+	{
+		for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
+		{
+			for(std::size_t x = -1 * std::min(0, x0); x < (std::size_t)fw; ++x)
+			{
+				assert(x >= 0);
+				assert(y >= 0);
+				assert(x < image.width());
+				assert(y < image.height());
+				auto& c = image.getPixel(x, y);
+
+				assert(x0 + x >= 0);
+				assert(y0 + y >= 0);
+				assert(x0 + x < pixbuf.width);
+				assert(y0 + y < pixbuf.height);
+
+				if (!has_restriction || c == restriction_colour)
+				{
+					pixbuf.addPixel(x0 + x, y0 + y, c);
+				}
+			}
+		}
+	}
+	else
+	{
+		for(std::size_t y = -1 * std::min(0, y0); y < (std::size_t)fh; ++y)
+		{
+			for(std::size_t x = -1 * std::min(0, x0); x < (std::size_t)fw; ++x)
+			{
+				assert(x >= 0);
+				assert(y >= 0);
+				assert(x < image.width());
+				assert(y < image.height());
+				auto& c = image.getPixel(x, y);
+
+				assert(x0 + x >= 0);
+				assert(y0 + y >= 0);
+				assert(x0 + x < pixbuf.width);
+				assert(y0 + y < pixbuf.height);
+
+				if (!has_restriction || c == restriction_colour)
+				{
+					pixbuf.setPixel(x0 + x, y0 + y, c);
+				}
 			}
 		}
 	}
 }
+#endif
 
 void Painter::drawRestrictedImage(int x0, int y0, Colour const& colour, const Drawable& image)
 {
diff --git a/plugingui/pixelbuffer.cc b/plugingui/pixelbuffer.cc
index 360ad06..1df1d5a 100644
--- a/plugingui/pixelbuffer.cc
+++ b/plugingui/pixelbuffer.cc
@@ -29,6 +29,7 @@
 #include <cassert>
 
 #include <cstdlib>
+#include <cstring>
 
 namespace GUI
 {
@@ -47,43 +48,63 @@ PixelBuffer::~PixelBuffer()
 void PixelBuffer::realloc(std::size_t width, std::size_t height)
 {
 	free(buf);
-	buf = (unsigned char *)calloc(width * height, 3);
+	buf = (std::uint8_t *)calloc(width * height, 3);
 	this->width = width;
 	this->height = height;
 }
 
 #define PX(k) ((x + y * width) * 3 + k)
-void PixelBuffer::setPixel(std::size_t x, std::size_t y,
-                           unsigned char red,
-                           unsigned char green,
-                           unsigned char blue,
-                           unsigned char alpha)
+void PixelBuffer::setPixel(std::size_t x, std::size_t y, const Colour& c)
 {
-	assert(x < width);
-	assert(y < height);
-
-	if(alpha == 0)
+	if(c.alpha() == 0)
 	{
 		return;
 	}
 
-	if(alpha < 255)
+	if(c.alpha() < 255)
 	{
-		unsigned int a = alpha;
-		unsigned int b = 255 - alpha;
+		unsigned int a = c.alpha();
+		unsigned int b = 255 - a;
 
-		buf[PX(0)] = (unsigned char)(((int)red   * a + (int)buf[PX(0)] * b) / 255);
-		buf[PX(1)] = (unsigned char)(((int)green * a + (int)buf[PX(1)] * b) / 255);
-		buf[PX(2)] = (unsigned char)(((int)blue  * a + (int)buf[PX(2)] * b) / 255);
+		std::uint8_t* pixel = &buf[PX(0)];
+		*pixel = (std::uint8_t)(((int)c.red()   * a + (int)*pixel * b) / 255);
+		++pixel;
+		*pixel = (std::uint8_t)(((int)c.green() * a + (int)*pixel * b) / 255);
+		++pixel;
+		*pixel = (std::uint8_t)(((int)c.blue()  * a + (int)*pixel * b) / 255);
 	}
 	else
 	{
-		buf[PX(0)] = red;
-		buf[PX(1)] = green;
-		buf[PX(2)] = blue;
+		memcpy(&buf[PX(0)], c.data(), 3);
+	}
+}
+
+void PixelBuffer::writeLine(std::size_t x, std::size_t y,
+                            const std::uint8_t* line, std::size_t len)
+{
+	std::uint8_t* target = &buf[PX(0)];
+	while(len)
+	{
+		if(line[3] == 0xff)
+		{
+			memcpy(target, line, 3);
+		}
+		else
+		{
+			unsigned int a = line[3];
+			unsigned int b = 255 - a;
+
+			target[0] = (std::uint8_t)(((int)line[0] * a + (int)target[0] * b) / 255);
+			target[1] = (std::uint8_t)(((int)line[1] * a + (int)target[1] * b) / 255);
+			target[2] = (std::uint8_t)(((int)line[2] * a + (int)target[2] * b) / 255);
+		}
+		target += 3;
+		line += 4;
+		--len;
 	}
 }
 
+
 PixelBufferAlpha::PixelBufferAlpha(std::size_t width, std::size_t height)
 	: managed(true)
 	, buf(nullptr)
@@ -104,30 +125,110 @@ PixelBufferAlpha::~PixelBufferAlpha()
 void PixelBufferAlpha::realloc(std::size_t width, std::size_t height)
 {
 	free(buf);
-	buf = (unsigned char *)calloc(width * height, 4);
+	buf = (std::uint8_t *)calloc(width * height, 4);
 	this->width = width;
 	this->height = height;
 }
 
+void PixelBufferAlpha::clear()
+{
+	memset(buf, 0, width * height * 4);
+}
+
 #undef PX
 #define PX(k) ((x + y * width) * 4 + k)
-void PixelBufferAlpha::setPixel(std::size_t x, std::size_t y,
-                                unsigned char red,
-                                unsigned char green,
-                                unsigned char blue,
-                                unsigned char alpha)
+//void PixelBufferAlpha::setPixel(std::size_t x, std::size_t y,
+//                                std::uint8_t red,
+//                                std::uint8_t green,
+//                                std::uint8_t blue,
+//                                std::uint8_t alpha)
+//{
+//	//assert(x < width);
+//	//assert(y < height);
+//
+//	std::uint8_t* pixel = &buf[PX(0)];
+//	*pixel = red;
+//	++pixel;
+//	*pixel = green;
+//	++pixel;
+//	*pixel = blue;
+//	++pixel;
+//	*pixel = alpha;
+//}
+
+void PixelBufferAlpha::setPixel(std::size_t x, std::size_t y, const Colour& c)
 {
-	assert(x < width);
-	assert(y < height);
+	std::uint8_t* pixel = &buf[PX(0)];
+	*pixel = c.red();
+	++pixel;
+	*pixel = c.green();
+	++pixel;
+	*pixel = c.blue();
+	++pixel;
+	*pixel = c.alpha();
+}
 
-	buf[PX(0)] = red;
-	buf[PX(1)] = green;
-	buf[PX(2)] = blue;
-	buf[PX(3)] = alpha;
+void PixelBufferAlpha::writeLine(std::size_t x, std::size_t y,
+                                 const std::uint8_t* line, std::size_t len)
+{
+	auto offset = &buf[PX(0)];
+	if(x + y * width + len > width * height)
+	{
+		return; // out of bounds
+	}
+	std::memcpy(offset, line, len * 4);
 }
 
+// SIMD: https://github.com/WojciechMula/toys/blob/master/blend_32bpp/blend_32bpp.c
+
+void PixelBufferAlpha::blendLine(std::size_t x, std::size_t y,
+                                 const std::uint8_t* line, std::size_t len)
+{
+	auto offset = &buf[PX(0)];
+	if(x + y * width + len > width * height)
+	{
+		return; // out of bounds
+	}
+
+	std::uint32_t* foreground = (std::uint32_t*)line;
+	std::uint32_t* background = (std::uint32_t*)offset;
+	for(std::size_t x = 0; x < len; ++x)
+	{
+		auto Rf =  *foreground & 0xff;
+		auto Gf = (*foreground >>  8) & 0xff;
+		auto Bf = (*foreground >> 16) & 0xff;
+		auto Af = (*foreground >> 24) & 0xff;
+
+		auto Rb =  *background & 0xff;
+		auto Gb = (*background >>  8) & 0xff;
+		auto Bb = (*background >> 16) & 0xff;
+		auto Ab = (*background >> 24) & 0xff;
+
+		auto R = (Rf * Af)/256 + Rb;
+		auto G = (Gf * Af)/256 + Gb;
+		auto B = (Bf * Af)/256 + Bb;
+
+		if (R > 255) R = 255;
+		if (G > 255) G = 255;
+		if (B > 255) B = 255;
+
+//		auto a = Ab / 255.0;
+//		auto b = Af / 255.0;
+//		b *= (1 - a);
+
+//		(Af / 255.0 * (1 - Ab / 255.0)) * 255
+		auto b = Ab * (255 - Af);
+
+		*background = R | (G << 8) | (B << 16) | b << 24;
+
+		++foreground;
+		++background;
+	}
+}
+
+
 // http://en.wikipedia.org/wiki/Alpha_compositing
-static inline void getAlpha(unsigned char _a, unsigned char _b,
+static inline void getAlpha(std::uint8_t _a, std::uint8_t _b,
                             float &a, float &b)
 {
 	a = _a / 255.0;
@@ -136,61 +237,80 @@ static inline void getAlpha(unsigned char _a, unsigned char _b,
 }
 
 void PixelBufferAlpha::addPixel(std::size_t x, std::size_t y,
-                                unsigned char red,
-                                unsigned char green,
-                                unsigned char blue,
-                                unsigned char alpha)
+                                std::uint8_t red,
+                                std::uint8_t green,
+                                std::uint8_t blue,
+                                std::uint8_t alpha)
 {
-	assert(x < width);
-	assert(y < height);
+	//assert(x < width);
+	//assert(y < height);
 
 	if(alpha == 0)
 	{
 		return;
 	}
 
+	std::uint8_t* pixel = &buf[PX(0)];
+
 	if(alpha < 255)
 	{
 		float a, b;
 		getAlpha(alpha, buf[PX(3)], a, b);
 
-		buf[PX(0)] = (unsigned char)((float)red   * a + (float)buf[PX(0)] * b);
-		buf[PX(0)] /= (a + b);
-		buf[PX(1)] = (unsigned char)((float)green * a + (float)buf[PX(1)] * b);
-		buf[PX(1)] /= (a + b);
-		buf[PX(2)] = (unsigned char)((float)blue  * a + (float)buf[PX(2)] * b);
-		buf[PX(2)] /= (a + b);
-
-		buf[PX(3)] = (a + b) * 255;
+		*pixel = (std::uint8_t)((red   * a + *pixel * b) / (a + b));
+		++pixel;
+		*pixel = (std::uint8_t)((green * a + *pixel * b) / (a + b));
+		++pixel;
+		*pixel = (std::uint8_t)((blue  * a + *pixel * b) / (a + b));
+		++pixel;
+		*pixel = (a + b) * 255;
 	}
 	else
 	{
-		buf[PX(0)] = red;
-		buf[PX(1)] = green;
-		buf[PX(2)] = blue;
-		buf[PX(3)] = alpha;
+		*pixel = red;
+		++pixel;
+		*pixel = green;
+		++pixel;
+		*pixel = blue;
+		++pixel;
+		*pixel = alpha;
 	}
 }
 
 void PixelBufferAlpha::addPixel(std::size_t x, std::size_t y, const Colour& c)
 {
-	addPixel(x, y,
-	         c.red() * 255, c.green() * 255, c.blue() * 255, c.alpha() * 255);
+	addPixel(x, y, c.red(), c.green(), c.blue(), c.alpha());
 }
 
 void PixelBufferAlpha::pixel(std::size_t x, std::size_t y,
-                             unsigned char* red,
-                             unsigned char* green,
-                             unsigned char* blue,
-                             unsigned char* alpha) const
-{
-	assert(x < width);
-	assert(y < height);
-
-	*red = buf[PX(0)];
-	*green = buf[PX(1)];
-	*blue = buf[PX(2)];
-	*alpha = buf[PX(3)];
+                             std::uint8_t* red,
+                             std::uint8_t* green,
+                             std::uint8_t* blue,
+                             std::uint8_t* alpha) const
+{
+	//assert(x < width);
+	//assert(y < height);
+
+	std::uint8_t* pixel = &buf[PX(0)];
+	*red = *pixel;
+	++pixel;
+	*green = *pixel;
+	++pixel;
+	*blue = *pixel;
+	++pixel;
+	*alpha = *pixel;
+}
+
+const Colour& PixelBufferAlpha::pixel(std::size_t x, std::size_t y) const
+{
+	static Colour c;
+	c = Colour(buf[PX(0)],  buf[PX(1)], buf[PX(2)], buf[PX(3)]);
+	return c;
+}
+
+const std::uint8_t* PixelBufferAlpha::getLine(std::size_t x, std::size_t y) const
+{
+	return &buf[PX(0)];
 }
 
 } // GUI::
diff --git a/plugingui/pixelbuffer.h b/plugingui/pixelbuffer.h
index 71869a0..499940d 100644
--- a/plugingui/pixelbuffer.h
+++ b/plugingui/pixelbuffer.h
@@ -41,13 +41,12 @@ public:
 
 	void realloc(std::size_t width, std::size_t height);
 
-	void setPixel(std::size_t x, std::size_t y,
-	              unsigned char red,
-	              unsigned char green,
-	              unsigned char blue,
-	              unsigned char alpha);
+	void setPixel(std::size_t x, std::size_t y, const Colour& c);
 
-	unsigned char* buf{nullptr};
+	void writeLine(std::size_t x, std::size_t y,
+	               const std::uint8_t* line, std::size_t len);
+
+	std::uint8_t* buf{nullptr};
 	std::size_t width{0};
 	std::size_t height{0};
 };
@@ -61,28 +60,35 @@ public:
 
 	void realloc(std::size_t width, std::size_t height);
 
-	void setPixel(std::size_t x, std::size_t y,
-	              unsigned char red,
-	              unsigned char green,
-	              unsigned char blue,
-	              unsigned char alpha);
+	void clear();
+
+	void setPixel(std::size_t x, std::size_t y, const Colour& c);
+
+	void writeLine(std::size_t x, std::size_t y,
+	               const std::uint8_t* line, std::size_t len);
+	void blendLine(std::size_t x, std::size_t y,
+	               const std::uint8_t* line, std::size_t len);
 
 	void addPixel(std::size_t x, std::size_t y,
-	              unsigned char red,
-	              unsigned char green,
-	              unsigned char blue,
-	              unsigned char alpha);
+	              std::uint8_t red,
+	              std::uint8_t green,
+	              std::uint8_t blue,
+	              std::uint8_t alpha);
 
 	void addPixel(std::size_t x, std::size_t y, const Colour& c);
 
 	void pixel(std::size_t x, std::size_t y,
-	           unsigned char* red,
-	           unsigned char* green,
-	           unsigned char* blue,
-	           unsigned char* alpha) const;
+	           std::uint8_t* red,
+	           std::uint8_t* green,
+	           std::uint8_t* blue,
+	           std::uint8_t* alpha) const;
+
+	const Colour& pixel(std::size_t x, std::size_t y) const;
+
+	const std::uint8_t* getLine(std::size_t x, std::size_t y) const;
 
 	bool managed{false};
-	unsigned char* buf{nullptr};
+	std::uint8_t* buf{nullptr};
 	std::size_t width{0};
 	std::size_t height{0};
 	int x{0};
diff --git a/plugingui/texture.cc b/plugingui/texture.cc
index 6dc6441..39d417d 100644
--- a/plugingui/texture.cc
+++ b/plugingui/texture.cc
@@ -59,4 +59,14 @@ const Colour& Texture::getPixel(size_t x, size_t y) const
 	return image.getPixel(x + _x, y + _y);
 }
 
+const std::uint8_t* Texture::line(std::size_t y) const
+{
+	return image.line(y + _y);
+}
+
+bool Texture::hasAlpha() const
+{
+	return true;
+}
+
 } // GUI::
diff --git a/plugingui/texture.h b/plugingui/texture.h
index c165f19..e5b0472 100644
--- a/plugingui/texture.h
+++ b/plugingui/texture.h
@@ -49,6 +49,8 @@ public:
 	size_t height() const override;
 
 	const Colour& getPixel(size_t x, size_t y) const override;
+	const std::uint8_t* line(std::size_t y) const override;
+	bool hasAlpha() const override;
 
 private:
 	std::size_t _x;
diff --git a/plugingui/texturedbox.cc b/plugingui/texturedbox.cc
index a03eecd..21bf946 100644
--- a/plugingui/texturedbox.cc
+++ b/plugingui/texturedbox.cc
@@ -133,4 +133,15 @@ const Colour& TexturedBox::getPixel(std::size_t x, std::size_t y) const
 	return outOfRange;
 }
 
+const std::uint8_t* TexturedBox::line(std::size_t y) const
+{
+	// TODO: Gather line into temporary buffer?
+	return nullptr;
+}
+
+bool TexturedBox::hasAlpha() const
+{
+	return true;
+}
+
 } // GUI::
diff --git a/plugingui/texturedbox.h b/plugingui/texturedbox.h
index dc84183..0ff0490 100644
--- a/plugingui/texturedbox.h
+++ b/plugingui/texturedbox.h
@@ -89,6 +89,8 @@ public:
 	void setSize(std::size_t width, std::size_t height);
 
 	const Colour& getPixel(std::size_t x, std::size_t y) const override;
+	const std::uint8_t* line(std::size_t y) const override;
+	bool hasAlpha() const override;
 
 private:
 	Texture seg_a;
diff --git a/plugingui/window.cc b/plugingui/window.cc
index a9deed5..acde008 100644
--- a/plugingui/window.cc
+++ b/plugingui/window.cc
@@ -349,8 +349,6 @@ bool Window::updateBuffer()
 			update_height = ((int)wpixbuf.height - pixel_buffer->y);
 		}
 
-		std::uint8_t r, g, b, a;
-
 		auto from_x  = (int)dirty_rect.x1 - pixel_buffer->x;
 		from_x = std::max(0, from_x);
 		auto from_y  = (int)dirty_rect.y1 - pixel_buffer->y;
@@ -361,13 +359,17 @@ bool Window::updateBuffer()
 		auto to_y = (int)dirty_rect.y2 - pixel_buffer->y;
 		to_y = std::min(to_y, (int)update_height);
 
+		if(to_x < from_x)
+		{
+			continue;
+		}
+
 		for(int y = from_y; y < to_y; y++)
 		{
-			for(int x = from_x; x < to_x; x++)
-			{
-				pixel_buffer->pixel(x, y, &r, &g, &b, &a);
-				wpixbuf.setPixel(x + pixel_buffer->x, y + pixel_buffer->y, r, g, b, a);
-			}
+			wpixbuf.writeLine(pixel_buffer->x + from_x,
+			                  pixel_buffer->y + y,
+			                  pixel_buffer->getLine(from_x, y),
+			                  to_x - from_x);
 		}
 	}