ui/gfx/image/image_ios.mm

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/gfx/image/image.h"
   6
   7 #import <UIKit/UIKit.h>
   8 #include <cmath>
   9 #include <limits>
  10
  11 #include "base/logging.h"
  12 #include "base/mac/scoped_cftyperef.h"
  13 #include "base/mac/scoped_nsobject.h"
  14 #include "ui/gfx/geometry/size.h"
  15 #include "ui/gfx/image/image_png_rep.h"
  16 #include "ui/gfx/image/image_skia.h"
  17 #include "ui/gfx/image/image_skia_util_ios.h"
  18
  19 namespace gfx {
  20 namespace internal {
  21
  22 namespace {
  23
  24 // Returns a 16x16 red UIImage to visually show when a UIImage cannot be
  25 // created from PNG data. Logs error as well.
  26 // Caller takes ownership of returned UIImage.
  27 UIImage* CreateErrorUIImage(float scale) {
  28   LOG(ERROR) << "Unable to decode PNG into UIImage.";
  29   base::ScopedCFTypeRef<CGColorSpaceRef> color_space(
  30       CGColorSpaceCreateDeviceRGB());
  31   base::ScopedCFTypeRef<CGContextRef> context(CGBitmapContextCreate(
  32       NULL,  // Allow CG to allocate memory.
  33       16,    // width
  34       16,    // height
  35       8,     // bitsPerComponent
  36       0,     // CG will calculate by default.
  37       color_space,
  38       kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
  39   CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0);
  40   CGContextFillRect(context, CGRectMake(0.0, 0.0, 16, 16));
  41   base::ScopedCFTypeRef<CGImageRef> cg_image(
  42       CGBitmapContextCreateImage(context));
  43   return [[UIImage imageWithCGImage:cg_image.get()
  44                               scale:scale
  45                         orientation:UIImageOrientationUp] retain];
  46 }
  47
  48 // Converts from ImagePNGRep to UIImage.
  49 UIImage* CreateUIImageFromImagePNGRep(const gfx::ImagePNGRep& image_png_rep) {
  50   float scale = image_png_rep.scale;
  51   scoped_refptr<base::RefCountedMemory> png = image_png_rep.raw_data;
  52   CHECK(png.get());
  53   NSData* data = [NSData dataWithBytes:png->front() length:png->size()];
  54   UIImage* image = [[UIImage alloc] initWithData:data scale:scale];
  55   return image ? image : CreateErrorUIImage(scale);
  56 }
  57
  58 }  // namespace
  59
  60 scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromUIImage(
  61     UIImage* uiimage) {
  62   NSData* data = UIImagePNGRepresentation(uiimage);
  63
  64   if ([data length] == 0)
  65     return NULL;
  66
  67   scoped_refptr<base::RefCountedBytes> png_bytes(
  68       new base::RefCountedBytes());
  69   png_bytes->data().resize([data length]);
  70   [data getBytes:&png_bytes->data().at(0) length:[data length]];
  71   return png_bytes;
  72 }
  73
  74 UIImage* CreateUIImageFromPNG(
  75     const std::vector<gfx::ImagePNGRep>& image_png_reps) {
  76   float ideal_scale = ImageSkia::GetMaxSupportedScale();
  77
  78   if (image_png_reps.empty())
  79     return CreateErrorUIImage(ideal_scale);
  80
  81   // Find best match for |ideal_scale|.
  82   float smallest_diff = std::numeric_limits<float>::max();
  83   size_t closest_index = 0u;
  84   for (size_t i = 0; i < image_png_reps.size(); ++i) {
  85     float scale = image_png_reps[i].scale;
  86     float diff = std::abs(ideal_scale - scale);
  87     if (diff < smallest_diff) {
  88       smallest_diff = diff;
  89       closest_index = i;
  90     }
  91   }
  92
  93   return CreateUIImageFromImagePNGRep(image_png_reps[closest_index]);
  94 }
  95
  96 scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromImageSkia(
  97     const ImageSkia* skia) {
  98   // iOS does not expose libpng, so conversion from ImageSkia to PNG must go
  99   // through UIImage.
 100   // TODO(rohitrao): Rewrite the callers of this function to save the UIImage
 101   // representation in the gfx::Image.  If we're generating it, we might as well
 102   // hold on to it.
 103   const gfx::ImageSkiaRep& image_skia_rep = skia->GetRepresentation(1.0f);
 104   if (image_skia_rep.scale() != 1.0f)
 105     return NULL;
 106
 107   UIImage* image = UIImageFromImageSkiaRep(image_skia_rep);
 108   return Get1xPNGBytesFromUIImage(image);
 109 }
 110
 111 ImageSkia* ImageSkiaFromPNG(
 112     const std::vector<gfx::ImagePNGRep>& image_png_reps) {
 113   // iOS does not expose libpng, so conversion from PNG to ImageSkia must go
 114   // through UIImage.
 115   gfx::ImageSkia* image_skia = new gfx::ImageSkia();
 116   for (size_t i = 0; i < image_png_reps.size(); ++i) {
 117     base::scoped_nsobject<UIImage> uiimage(
 118         CreateUIImageFromImagePNGRep(image_png_reps[i]));
 119     gfx::ImageSkiaRep image_skia_rep = ImageSkiaRepOfScaleFromUIImage(
 120         uiimage, image_png_reps[i].scale);
 121     if (!image_skia_rep.is_null())
 122       image_skia->AddRepresentation(image_skia_rep);
 123   }
 124   return image_skia;
 125 }
 126
 127 gfx::Size UIImageSize(UIImage* image) {
 128   int width = static_cast<int>(image.size.width);
 129   int height = static_cast<int>(image.size.height);
 130   return gfx::Size(width, height);
 131 }
 132
 133 } // namespace internal
 134 } // namespace gfx