| /* |
| * Copyright 2013 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkBitmap.h" |
| #include "SkColorFilter.h" |
| #include "SkPaintPriv.h" |
| #include "SkImage.h" |
| #include "SkPaint.h" |
| #include "SkShaderBase.h" |
| #include "SkUtils.h" |
| #include "SkXfermodePriv.h" |
| |
| static bool changes_alpha(const SkPaint& paint) { |
| SkColorFilter* cf = paint.getColorFilter(); |
| return cf && !(cf->getFlags() & SkColorFilter::kAlphaUnchanged_Flag); |
| } |
| |
| bool SkPaintPriv::Overwrites(const SkPaint* paint, ShaderOverrideOpacity overrideOpacity) { |
| if (!paint) { |
| // No paint means we default to SRC_OVER, so we overwrite iff our shader-override |
| // is opaque, or we don't have one. |
| return overrideOpacity != kNotOpaque_ShaderOverrideOpacity; |
| } |
| |
| SkXfermode::SrcColorOpacity opacityType = SkXfermode::kUnknown_SrcColorOpacity; |
| |
| if (!changes_alpha(*paint)) { |
| const unsigned paintAlpha = paint->getAlpha(); |
| if (0xff == paintAlpha && overrideOpacity != kNotOpaque_ShaderOverrideOpacity && |
| (!paint->getShader() || paint->getShader()->isOpaque())) |
| { |
| opacityType = SkXfermode::kOpaque_SrcColorOpacity; |
| } else if (0 == paintAlpha) { |
| if (overrideOpacity == kNone_ShaderOverrideOpacity && !paint->getShader()) { |
| opacityType = SkXfermode::kTransparentBlack_SrcColorOpacity; |
| } else { |
| opacityType = SkXfermode::kTransparentAlpha_SrcColorOpacity; |
| } |
| } |
| } |
| |
| return SkXfermode::IsOpaque(paint->getBlendMode(), opacityType); |
| } |
| |
| bool SkPaintPriv::Overwrites(const SkBitmap& bitmap, const SkPaint* paint) { |
| return Overwrites(paint, bitmap.isOpaque() ? kOpaque_ShaderOverrideOpacity |
| : kNotOpaque_ShaderOverrideOpacity); |
| } |
| |
| bool SkPaintPriv::Overwrites(const SkImage* image, const SkPaint* paint) { |
| return Overwrites(paint, image->isOpaque() ? kOpaque_ShaderOverrideOpacity |
| : kNotOpaque_ShaderOverrideOpacity); |
| } |
| |
| void SkPaintPriv::ScaleFontMetrics(SkPaint::FontMetrics* metrics, SkScalar scale) { |
| metrics->fTop *= scale; |
| metrics->fAscent *= scale; |
| metrics->fDescent *= scale; |
| metrics->fBottom *= scale; |
| metrics->fLeading *= scale; |
| metrics->fAvgCharWidth *= scale; |
| metrics->fXMin *= scale; |
| metrics->fXMax *= scale; |
| metrics->fXHeight *= scale; |
| metrics->fUnderlineThickness *= scale; |
| metrics->fUnderlinePosition *= scale; |
| } |
| |
| bool SkPaintPriv::ShouldDither(const SkPaint& p, SkColorType dstCT) { |
| // The paint dither flag can veto. |
| if (!p.isDither()) { |
| return false; |
| } |
| |
| // We always dither 565 or 4444 when requested. |
| if (dstCT == kRGB_565_SkColorType || dstCT == kARGB_4444_SkColorType) { |
| return true; |
| } |
| |
| // Otherwise, dither is only needed for non-const paints. |
| return p.getImageFilter() || p.getMaskFilter() |
| || !p.getShader() || !as_SB(p.getShader())->isConstant(); |
| } |
| |
| int SkPaintPriv::ValidCountText(const void* text, size_t length, SkPaint::TextEncoding encoding) { |
| if (length == 0) { |
| return 0; |
| } |
| switch (encoding) { |
| case SkPaint::kUTF8_TextEncoding: return SkUTF8_CountUnichars(text, length); |
| case SkPaint::kUTF16_TextEncoding: return SkUTF16_CountUnichars(text, length); |
| case SkPaint::kUTF32_TextEncoding: return SkUTF32_CountUnichars(text, length); |
| case SkPaint::kGlyphID_TextEncoding: |
| if (SkIsAlign2(intptr_t(text)) && SkIsAlign2(length)) { |
| return length >> 1; |
| } |
| break; |
| } |
| return 0; |
| } |
| |