/**
* Extract either the color or image data from a SkBitmap into a SkStream.
* @param bitmap Bitmap to extract data from.
* @param srcRect Region in the bitmap to extract.
* @param extractAlpha Set to true to extract the alpha data or false to
* extract the color data.
* @param isTransparent Pointer to a bool to output whether the alpha is
* completely transparent. May be NULL. Only valid when
* extractAlpha == true.
* @return Unencoded image data, or NULL if either data was not
* available or alpha data was requested but the image was
* entirely transparent or opaque.
*/
static SkStream* extract_image_data(const SkBitmap& bitmap,
const SkIRect& srcRect,
bool extractAlpha, bool* isTransparent) {
SkColorType colorType = bitmap.colorType();
if (extractAlpha && (kIndex_8_SkColorType == colorType ||
kRGB_565_SkColorType == colorType)) {
if (isTransparent != NULL) {
*isTransparent = false;
}
return NULL;
}
SkAutoLockPixels lock(bitmap);
if (NULL == bitmap.getPixels()) {
return NULL;
}
bool isOpaque = true;
bool transparent = extractAlpha;
SkAutoTDelete<SkStream> stream;
switch (colorType) {
case kIndex_8_SkColorType:
if (!extractAlpha) {
stream.reset(extract_index8_image(bitmap, srcRect));
}
break;
case kARGB_4444_SkColorType:
stream.reset(extract_argb4444_data(bitmap, srcRect, extractAlpha,
&isOpaque, &transparent));
break;
case kRGB_565_SkColorType:
if (!extractAlpha) {
stream.reset(extract_rgb565_image(bitmap, srcRect));
}
break;
case kN32_SkColorType:
stream.reset(extract_argb8888_data(bitmap, srcRect, extractAlpha,
&isOpaque, &transparent));
break;
case kAlpha_8_SkColorType:
if (!extractAlpha) {
stream.reset(create_black_image());
} else {
stream.reset(extract_a8_alpha(bitmap, srcRect,
&isOpaque, &transparent));
}
break;
default:
SkASSERT(false);
}
if (isTransparent != NULL) {
*isTransparent = transparent;
}
if (extractAlpha && (transparent || isOpaque)) {
return NULL;
}
return stream.detach();
}
/**
* Extract either the color or image data from a SkBitmap into a SkStream.
* @param bitmap Bitmap to extract data from.
* @param srcRect Region in the bitmap to extract.
* @param extractAlpha Set to true to extract the alpha data or false to
* extract the color data.
* @param isTransparent Pointer to a bool to output whether the alpha is
* completely transparent. May be NULL. Only valid when
* extractAlpha == true.
* @return Unencoded image data, or NULL if either data was not
* available or alpha data was requested but the image was
* entirely transparent or opaque.
*/
static SkStream* extract_image_data(const SkBitmap& bitmap,
const SkIRect& srcRect,
bool extractAlpha, bool* isTransparent) {
SkColorType colorType = bitmap.colorType();
if (extractAlpha && (kIndex_8_SkColorType == colorType ||
kRGB_565_SkColorType == colorType)) {
if (isTransparent != NULL) {
*isTransparent = false;
}
return NULL;
}
bool isOpaque = true;
bool transparent = extractAlpha;
SkStream* stream = NULL;
bitmap.lockPixels();
switch (colorType) {
case kIndex_8_SkColorType:
if (!extractAlpha) {
stream = extract_index8_image(bitmap, srcRect);
}
break;
case kARGB_4444_SkColorType:
stream = extract_argb4444_data(bitmap, srcRect, extractAlpha,
&isOpaque, &transparent);
break;
case kRGB_565_SkColorType:
if (!extractAlpha) {
stream = extract_rgb565_image(bitmap, srcRect);
}
break;
case kN32_SkColorType:
stream = extract_argb8888_data(bitmap, srcRect, extractAlpha,
&isOpaque, &transparent);
break;
case kAlpha_8_SkColorType:
if (!extractAlpha) {
stream = create_black_image();
} else {
stream = extract_a8_alpha(bitmap, srcRect,
&isOpaque, &transparent);
}
break;
default:
SkASSERT(false);
}
bitmap.unlockPixels();
if (isTransparent != NULL) {
*isTransparent = transparent;
}
if (extractAlpha && (transparent || isOpaque)) {
SkSafeUnref(stream);
return NULL;
}
return stream;
}