From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 8 Oct 2013 10:39:23 +0000 (+0300)
Subject: Support for using Quartz to load images on OS X
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgui.git;a=commitdiff_plain;h=925757a29754bac7980b905b830d851811c50ba6

Support for using Quartz to load images on OS X
---

diff --git a/Build b/Build
index 4862e3d..b96da4d 100644
--- a/Build
+++ b/Build
@@ -43,6 +43,21 @@ package "mspgui"
 		require "libpng";
 	};
 
+	if_arch "darwin"
+	{
+		feature "quartz" "Include Quartz support for loading image files"
+		{
+			default "yes";
+		};
+		if_feature "quartz"
+		{
+			build_info
+			{
+				library "ApplicationServices.framework";
+			};
+		};
+	};
+
 	feature "opengl" "Include support for OpenGL contexts"
 	{
 		default "yes";
@@ -83,6 +98,10 @@ package "mspgui"
 		};
 		if_arch "darwin"
 		{
+			if_feature "quartz"
+			{
+				source "source/graphics/quartz";
+			};
 			overlay "cocoa";
 			if_feature "opengl"
 			{
diff --git a/source/graphics/quartz/quartzloader.cpp b/source/graphics/quartz/quartzloader.cpp
new file mode 100644
index 0000000..23f7abb
--- /dev/null
+++ b/source/graphics/quartz/quartzloader.cpp
@@ -0,0 +1,146 @@
+#include <algorithm>
+#include <CoreGraphics/CGColorSpace.h>
+#include <CoreGraphics/CGImage.h>
+#include <ImageIO/CGImageSource.h>
+// Avoid messing up sigc++ headers
+#undef nil
+#include "quartzloader.h"
+
+using namespace std;
+
+namespace {
+
+size_t get_bytes(void *info, void *buffer, size_t count)
+{
+	Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
+	char *cbuf = reinterpret_cast<char *>(buffer);
+	return io->read(cbuf, count);
+}
+
+off_t skip_forward(void *info, off_t count)
+{
+	Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
+
+	off_t i = 0;
+	char buf[1024];
+	while(i<count)
+		i += io->read(buf, min<unsigned>(sizeof(buf), count-i));
+
+	return i;
+}
+
+void rewind(void *info)
+{
+	Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
+	io->seek(0, Msp::IO::S_BEG);
+}
+
+CGDataProviderSequentialCallbacks callbacks =
+{
+	0,
+	&get_bytes,
+	&skip_forward,
+	&rewind,
+	0
+};
+
+} // namespace
+
+
+namespace Msp {
+namespace Graphics {
+
+struct QuartzLoader::Private
+{
+	CGDataProviderRef provider;
+	CGImageSourceRef source;
+};
+
+
+ImageLoader::Register<QuartzLoader> QuartzLoader::reg;
+
+QuartzLoader::QuartzLoader(IO::Seekable &io):
+	priv(new Private)
+{
+	priv->provider = CGDataProviderCreateSequential(&io, &callbacks);
+	priv->source = CGImageSourceCreateWithDataProvider(priv->provider, 0);
+}
+
+QuartzLoader::~QuartzLoader()
+{
+	CFRelease(priv->source);
+	CFRelease(priv->provider);
+	delete priv;
+}
+
+bool QuartzLoader::detect(const string &sig)
+{
+	CGImageSourceRef source = CGImageSourceCreateIncremental(0);
+	CFDataRef data = CFDataCreate(0, reinterpret_cast<const UInt8 *>(sig.data()), sig.size());
+	CGImageSourceUpdateData(source, data, false);
+	CGImageSourceStatus status = CGImageSourceGetStatus(source);
+	CFRelease(data);
+	CFRelease(source);
+
+	return status==kCGImageStatusIncomplete;
+}
+
+void QuartzLoader::load(Image::Data &data)
+{
+	CGImageRef image = CGImageSourceCreateImageAtIndex(priv->source, 0, 0);
+
+	try
+	{
+		data.width = CGImageGetWidth(image);
+		data.height = CGImageGetHeight(image);
+
+		CGColorSpaceRef color = CGImageGetColorSpace(image);
+		CGColorSpaceModel model = CGColorSpaceGetModel(color);
+		CGImageAlphaInfo alpha = CGImageGetAlphaInfo(image);
+		if(model==kCGColorSpaceModelRGB)
+		{
+			if(alpha==kCGImageAlphaLast)
+				data.fmt = RGBA;
+			else if(alpha==kCGImageAlphaNone || alpha==kCGImageAlphaNoneSkipFirst || alpha==kCGImageAlphaNoneSkipLast)
+				data.fmt = RGB;
+			else
+				throw unsupported_image_format("unknown alpha mode");
+		}
+		else
+			throw unsupported_image_format("unknown colorspace");
+
+		unsigned bytes_per_pixel = (CGImageGetBitsPerPixel(image)+7)/8;
+
+		CGDataProviderRef dp = CGImageGetDataProvider(image);
+		CFDataRef image_data = CGDataProviderCopyData(dp);
+		data.data = new char[data.width*data.height*bytes_per_pixel];
+		CFDataGetBytes(image_data, CFRangeMake(0, CFDataGetLength(image_data)), reinterpret_cast<UInt8 *>(data.data));
+		CFRelease(image_data);
+
+		CFRelease(image);
+
+		if(alpha==kCGImageAlphaNoneSkipFirst || alpha==kCGImageAlphaNoneSkipLast)
+		{
+			const char *src = data.data;
+			if(alpha==kCGImageAlphaNoneSkipFirst)
+				++src;
+			char *dest = data.data;
+			for(unsigned y=0; y<data.height; ++y)
+				for(unsigned x=0; x<data.width; ++x)
+				{
+					for(unsigned i=0; i<3; ++i)
+						dest[i] = src[i];
+					dest += 3;
+					src += 4;
+				}
+		}
+	}
+	catch(...)
+	{
+		CFRelease(image);
+		throw;
+	}
+}
+
+} // namespace Graphics
+} // namespace Msp
diff --git a/source/graphics/quartz/quartzloader.h b/source/graphics/quartz/quartzloader.h
new file mode 100644
index 0000000..d3bef7b
--- /dev/null
+++ b/source/graphics/quartz/quartzloader.h
@@ -0,0 +1,33 @@
+#ifndef MSP_GRAPHICS_QUARTZLOADER_H_
+#define MSP_GRAPHICS_QUARTZLOADER_H_
+
+#include <msp/graphics/imageloader.h>
+
+namespace Msp {
+namespace Graphics {
+
+class QuartzLoader: public ImageLoader
+{
+private:
+	struct Private;
+
+	Private *priv;
+
+	static Register<QuartzLoader> reg;
+
+public:
+	QuartzLoader(IO::Seekable &);
+	virtual ~QuartzLoader();
+
+	/* Experimentally found value, works for png and jpeg at least.  8 bytes
+	is not enough for Quartz to recognize png. */
+	static unsigned get_signature_size() { return 12; }
+	static bool detect(const std::string &);
+
+	virtual void load(Image::Data &);
+};
+
+} // namespace Graphics
+} // namespace Msp
+
+#endif