diff options
| -rw-r--r-- | app/gfx/icon_util.cc | 58 | ||||
| -rw-r--r-- | app/gfx/icon_util.h | 3 |
2 files changed, 43 insertions, 18 deletions
diff --git a/app/gfx/icon_util.cc b/app/gfx/icon_util.cc index 527798f..4134c90 100644 --- a/app/gfx/icon_util.cc +++ b/app/gfx/icon_util.cc @@ -8,6 +8,7 @@ #include "base/file_util.h" #include "base/gfx/size.h" #include "base/logging.h" +#include "base/scoped_ptr.h" #include "skia/ext/image_operations.h" #include "third_party/skia/include/core/SkBitmap.h" @@ -61,16 +62,33 @@ HICON IconUtil::CreateHICONFromSkBitmap(const SkBitmap& bitmap) { // Icons are generally created using an AND and XOR masks where the AND // specifies boolean transparency (the pixel is either opaque or - // transparent) and the XOR mask contains the actual image pixels. However, - // since our bitmap has an alpha channel, the AND monochrome bitmap won't - // actually be used for computing the pixel transparency. Since every icon - // must have an AND mask bitmap, we go ahead and create one so that we can - // associate it with the ICONINFO structure we'll later pass to - // ::CreateIconIndirect(). The monochrome bitmap is created such that all the - // pixels are opaque. - HBITMAP mono_bitmap = ::CreateBitmap(bitmap.width(), bitmap.height(), - 1, 1, NULL); + // transparent) and the XOR mask contains the actual image pixels. If the XOR + // mask bitmap has an alpha channel, the AND monochrome bitmap won't + // actually be used for computing the pixel transparency. Even though all our + // bitmap has an alpha channel, Windows might not agree when all alpha values + // are zero. So the monochrome bitmap is created with all pixels transparent + // for this case. Otherwise, it is created with all pixels opaque. + bool bitmap_has_alpha_channel = PixelsHaveAlpha( + static_cast<const uint32*>(bitmap.getPixels()), + bitmap.width() * bitmap.height()); + + scoped_array<uint8> mask_bits; + if (!bitmap_has_alpha_channel) { + // Bytes per line with paddings to make it word alignment. + size_t bytes_per_line = (bitmap.width() + 0xF) / 16 * 2; + size_t mask_bits_size = bytes_per_line * bitmap.height(); + + mask_bits.reset(new uint8[mask_bits_size]); + DCHECK(mask_bits.get()); + + // Make all pixels transparent. + memset(mask_bits.get(), 0xFF, mask_bits_size); + } + + HBITMAP mono_bitmap = ::CreateBitmap(bitmap.width(), bitmap.height(), 1, 1, + reinterpret_cast<LPVOID>(mask_bits.get())); DCHECK(mono_bitmap); + ICONINFO icon_info; icon_info.fIcon = TRUE; icon_info.xHotspot = 0; @@ -149,19 +167,13 @@ SkBitmap* IconUtil::CreateSkBitmapFromHICON(HICON icon, const gfx::Size& s) { memcpy(bitmap->getPixels(), static_cast<void*>(bits), num_pixels * 4); // Finding out whether the bitmap has an alpha channel. - bool bitmap_has_alpha_channel = false; - unsigned int* p = static_cast<unsigned int*>(bitmap->getPixels()); - for (unsigned int* end = p + num_pixels; p != end; ++p) { - if ((*p & 0xff000000) != 0) { - bitmap_has_alpha_channel = true; - break; - } - } + bool bitmap_has_alpha_channel = PixelsHaveAlpha( + static_cast<const uint32*>(bitmap->getPixels()), num_pixels); // If the bitmap does not have an alpha channel, we need to build it using // the previously captured AND mask. Otherwise, we are done. if (!bitmap_has_alpha_channel) { - p = static_cast<unsigned int*>(bitmap->getPixels()); + unsigned int* p = static_cast<unsigned int*>(bitmap->getPixels()); for (size_t i = 0; i < num_pixels; ++p, ++i) { DCHECK_EQ((*p & 0xff000000), 0); if (opaque[i]) @@ -264,6 +276,16 @@ int IconUtil::GetIconDimensionCount() { return sizeof(icon_dimensions_) / sizeof(icon_dimensions_[0]); } +bool IconUtil::PixelsHaveAlpha(const uint32* pixels, size_t num_pixels) { + for (const uint32* end = pixels + num_pixels; pixels != end; ++pixels) { + if ((*pixels & 0xff000000) != 0) { + return true; + } + } + + return false; +} + void IconUtil::InitializeBitmapHeader(BITMAPV5HEADER* header, int width, int height) { DCHECK(header); diff --git a/app/gfx/icon_util.h b/app/gfx/icon_util.h index 1ecbfb56..65d3d80 100644 --- a/app/gfx/icon_util.h +++ b/app/gfx/icon_util.h @@ -128,6 +128,9 @@ class IconUtil { // Returns how many icon dimensions are defined. static int GetIconDimensionCount(); + // Returns true if any pixel in the given pixels buffer has an non-zero alpha. + static bool PixelsHaveAlpha(const uint32* pixels, size_t num_pixels); + // A helper function that initializes a BITMAPV5HEADER structure with a set // of values. static void InitializeBitmapHeader(BITMAPV5HEADER* header, int width, |