source/graphics/quartz/quartzloader.cpp

   1 #include <algorithm>
   2 #include <CoreGraphics/CGColorSpace.h>
   3 #include <CoreGraphics/CGImage.h>
   4 #include <ImageIO/CGImageSource.h>
   5 // Avoid messing up sigc++ headers
   6 #undef nil
   7 #include "quartzloader.h"
   8
   9 using namespace std;
  10
  11 namespace {
  12
  13 size_t get_bytes(void *info, void *buffer, size_t count)
  14 {
  15         Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
  16         char *cbuf = reinterpret_cast<char *>(buffer);
  17         return io->read(cbuf, count);
  18 }
  19
  20 off_t skip_forward(void *info, off_t count)
  21 {
  22         Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
  23
  24         off_t i = 0;
  25         char buf[1024];
  26         while(i<count)
  27                 i += io->read(buf, min<unsigned>(sizeof(buf), count-i));
  28
  29         return i;
  30 }
  31
  32 void rewind(void *info)
  33 {
  34         Msp::IO::Seekable *io = reinterpret_cast<Msp::IO::Seekable *>(info);
  35         io->seek(0, Msp::IO::S_BEG);
  36 }
  37
  38 CGDataProviderSequentialCallbacks callbacks =
  39 {
  40         0,
  41         &get_bytes,
  42         &skip_forward,
  43         &rewind,
  44         0
  45 };
  46
  47 } // namespace
  48
  49
  50 namespace Msp {
  51 namespace Graphics {
  52
  53 struct QuartzLoader::Private
  54 {
  55         CGDataProviderRef provider;
  56         CGImageSourceRef source;
  57 };
  58
  59
  60 ImageLoader::Register<QuartzLoader> QuartzLoader::reg;
  61
  62 QuartzLoader::QuartzLoader(IO::Seekable &io):
  63         priv(new Private)
  64 {
  65         priv->provider = CGDataProviderCreateSequential(&io, &callbacks);
  66         priv->source = CGImageSourceCreateWithDataProvider(priv->provider, 0);
  67 }
  68
  69 QuartzLoader::~QuartzLoader()
  70 {
  71         CFRelease(priv->source);
  72         CFRelease(priv->provider);
  73         delete priv;
  74 }
  75
  76 bool QuartzLoader::detect(const string &sig)
  77 {
  78         CGImageSourceRef source = CGImageSourceCreateIncremental(0);
  79         CFDataRef data = CFDataCreate(0, reinterpret_cast<const UInt8 *>(sig.data()), sig.size());
  80         CGImageSourceUpdateData(source, data, false);
  81         CGImageSourceStatus status = CGImageSourceGetStatus(source);
  82         CFRelease(data);
  83         CFRelease(source);
  84
  85         return status==kCGImageStatusIncomplete || status==kCGImageStatusReadingHeader;
  86 }
  87
  88 void QuartzLoader::load(Image::Data &data)
  89 {
  90         CGImageRef image = CGImageSourceCreateImageAtIndex(priv->source, 0, 0);
  91         if(!image)
  92                 throw bad_image_data("null image");
  93
  94         try
  95         {
  96                 data.width = CGImageGetWidth(image);
  97                 data.height = CGImageGetHeight(image);
  98                 data.stride = CGImageGetBytesPerRow(image);
  99
 100                 CGColorSpaceRef color = CGImageGetColorSpace(image);
 101                 CGColorSpaceModel model = CGColorSpaceGetModel(color);
 102                 CGImageAlphaInfo alpha = CGImageGetAlphaInfo(image);
 103                 if(model==kCGColorSpaceModelRGB)
 104                 {
 105                         if(alpha==kCGImageAlphaLast)
 106                                 data.fmt = RGBA;
 107                         else if(alpha==kCGImageAlphaNoneSkipLast || alpha==kCGImageAlphaNoneSkipFirst)
 108                                 data.fmt = RGBX;
 109                         else if(alpha==kCGImageAlphaNone)
 110                                 data.fmt = RGB;
 111                         else
 112                                 throw unsupported_image_format("unknown alpha mode");
 113                 }
 114                 else
 115                         throw unsupported_image_format("unknown colorspace");
 116
 117                 CGDataProviderRef dp = CGImageGetDataProvider(image);
 118                 CFDataRef image_data = CGDataProviderCopyData(dp);
 119                 data.data = new char[data.height*data.stride];
 120                 unsigned offset = (alpha==kCGImageAlphaNoneSkipFirst);
 121                 CFRange range = CFRangeMake(offset, CFDataGetLength(image_data)-offset);
 122                 CFDataGetBytes(image_data, range, reinterpret_cast<UInt8 *>(data.data));
 123                 CFRelease(image_data);
 124
 125                 CFRelease(image);
 126         }
 127         catch(...)
 128         {
 129                 CFRelease(image);
 130                 throw;
 131         }
 132 }
 133
 134 } // namespace Graphics
 135 } // namespace Msp