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Advanced blending

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This commit is contained in:
Jakub Melka
2021-01-23 19:03:12 +01:00
parent ea62e6ee32
commit 443c656a46
6 changed files with 442 additions and 0 deletions
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27
Pdf4QtLib/sources/pdftransparencyrenderer.h
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@ -39,6 +39,9 @@ public:
constexpr static uint8_t INVALID_CHANNEL_INDEX = 0xFF;
constexpr bool operator==(const PDFPixelFormat&) const = default;
constexpr bool operator!=(const PDFPixelFormat&) const = default;
constexpr bool hasProcessColors() const { return m_processColors > 0; }
constexpr bool hasSpotColors() const { return m_spotColors > 0; }
constexpr bool hasShapeChannel() const { return m_flags & FLAG_HAS_SHAPE_CHANNEL; }
@ -60,6 +63,8 @@ public:
constexpr uint8_t getProcessColorChannelIndexEnd() const { return hasProcessColors() ? getProcessColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getSpotColorChannelIndexStart() const { return hasSpotColors() ? getProcessColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getSpotColorChannelIndexEnd() const { return hasSpotColors() ? getSpotColorChannelIndexStart() + getSpotColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getColorChannelIndexStart() const { return (hasProcessColors() || hasSpotColors()) ? 0 : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getColorChannelIndexEnd() const { return (hasProcessColors() || hasSpotColors()) ? (m_processColors + m_spotColors) : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getShapeChannelIndex() const { return hasShapeChannel() ? getProcessColorChannelCount() + getSpotColorChannelCount() : INVALID_CHANNEL_INDEX; }
constexpr uint8_t getOpacityChannelIndex() const { return hasShapeChannel() ? getProcessColorChannelCount() + getSpotColorChannelCount() + getShapeChannelCount() : INVALID_CHANNEL_INDEX; }
@ -159,6 +164,26 @@ public:
/// Extract process colors into another bitmap
PDFFloatBitmap extractProcessColors();
/// Performs bitmap blending, pixel format of source and target must be the same.
/// Blending algorithm uses the one from chapter 11.4.8 in the PDF 2.0 specification.
/// Bitmap size must be equal for all three bitmaps (source, target and soft mask).
/// \param source Source bitmap
/// \param target Target bitmap
/// \param backdrop Backdrop
/// \param initialBackdrop Initial backdrop
/// \param softMask Soft mask
/// \param alphaIsShape Both soft mask and constant alpha are shapes and not opacity?
/// \param constantAlpha Constant alpha, can mean shape or opacity
/// \param mode Blend mode
void blend(const PDFFloatBitmap& source,
PDFFloatBitmap& target,
const PDFFloatBitmap& backdrop,
const PDFFloatBitmap& initialBackdrop,
PDFFloatBitmap& softMask,
bool alphaIsShape,
PDFColorComponent constantAlpha,
BlendMode mode);
private:
void fillChannel(size_t channel, PDFColorComponent value);
@ -247,6 +272,8 @@ private:
PDFColorSpacePointer blendColorSpace;
};
void removeInitialBackdrop();
PDFFloatBitmapWithColorSpace* getInitialBackdrop();
PDFFloatBitmapWithColorSpace* getImmediateBackdrop();
PDFFloatBitmapWithColorSpace* getBackdrop();