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https://github.com/JakubMelka/PDF4QT.git
synced 2025-06-05 21:59:17 +02:00
Advanced blending
This commit is contained in:
Jakub Melka
@ -123,6 +123,219 @@ PDFFloatBitmap PDFFloatBitmap::extractProcessColors()
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return result;
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}
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void PDFFloatBitmap::blend(const PDFFloatBitmap& source,
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PDFFloatBitmap& target,
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const PDFFloatBitmap& backdrop,
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const PDFFloatBitmap& initialBackdrop,
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PDFFloatBitmap& softMask,
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bool alphaIsShape,
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PDFColorComponent constantAlpha,
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BlendMode mode)
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{
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Q_ASSERT(source.getWidth() == target.getWidth());
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Q_ASSERT(source.getHeight() == target.getHeight());
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Q_ASSERT(source.getPixelFormat() == target.getPixelFormat());
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Q_ASSERT(source.getWidth() == softMask.getWidth());
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Q_ASSERT(source.getHeight() == softMask.getHeight());
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Q_ASSERT(softMask.getPixelFormat() == PDFPixelFormat::createOpacityMask());
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const size_t width = source.getWidth();
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const size_t height = source.getHeight();
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const PDFPixelFormat pixelFormat = source.getPixelFormat();
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const uint8_t shapeChannel = pixelFormat.getShapeChannelIndex();
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const uint8_t opacityChannel = pixelFormat.getOpacityChannelIndex();
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const uint8_t colorChannelStart = pixelFormat.getColorChannelIndexStart();
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const uint8_t colorChannelEnd = pixelFormat.getColorChannelIndexEnd();
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std::vector<PDFColorComponent> B_i(source.getPixelSize(), 0.0f);
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for (size_t x = 0; x < width; ++x)
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{
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for (size_t y = 0; y < height; ++y)
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{
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PDFColorBuffer sourceColor = source.getPixel(x, y);
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PDFColorBuffer targetColor = target.getPixel(x, y);
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PDFColorBuffer backdropColor = backdrop.getPixel(x, y);
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PDFColorBuffer initialBackdropColor = initialBackdrop.getPixel(x, y);
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PDFColorBuffer alphaColorBuffer = softMask.getPixel(x, y);
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const PDFColorComponent softMaskValue = alphaColorBuffer[0];
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const PDFColorComponent f_j_i = sourceColor[shapeChannel];
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const PDFColorComponent f_m_i = alphaIsShape ? softMaskValue : 1.0f;
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const PDFColorComponent f_k_i = alphaIsShape ? constantAlpha : 1.0f;
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const PDFColorComponent q_m_i = !alphaIsShape ? softMaskValue : 1.0f;
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const PDFColorComponent q_k_i = !alphaIsShape ? constantAlpha : 1.0f;
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const PDFColorComponent f_s_i = f_j_i * f_m_i * f_k_i;
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const PDFColorComponent alpha_j_i = sourceColor[opacityChannel];
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const PDFColorComponent alpha_s_i = alpha_j_i * (f_m_i * q_m_i) * (f_k_i * q_k_i);
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const PDFColorComponent alpha_g_b = backdropColor[opacityChannel];
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const PDFColorComponent alpha_0 = initialBackdropColor[opacityChannel];
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const PDFColorComponent f_g_i_1 = targetColor[shapeChannel];
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const PDFColorComponent alpha_g_i_1 = targetColor[opacityChannel];
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const PDFColorComponent alpha_b = backdropColor[opacityChannel];
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const PDFColorComponent f_g_i = PDFBlendFunction::blend_Union(f_g_i_1, f_s_i);
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const PDFColorComponent alpha_g_i = (1.0f - f_s_i) * alpha_g_i_1 + (f_s_i - alpha_s_i) * alpha_g_b + alpha_s_i;
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const PDFColorComponent alpha_i_1 = PDFBlendFunction::blend_Union(alpha_0, alpha_g_i_1);
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const PDFColorComponent alpha_i = PDFBlendFunction::blend_Union(alpha_0, alpha_g_i);
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if (qFuzzyIsNull(alpha_g_i))
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{
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// If alpha_i is zero, then color is undefined
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continue;
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}
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std::fill(B_i.begin(), B_i.end(), 0.0f);
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// Calculate blended pixel
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if (PDFBlendModeInfo::isSeparable(mode))
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{
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// Separable blend mode - process each color separately
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const bool isProcessColorSubtractive = pixelFormat.hasProcessColorsSubtractive();
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const bool isSpotColorSubtractive = pixelFormat.hasSpotColorsSubtractive();
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if (pixelFormat.hasProcessColors())
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{
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if (!isProcessColorSubtractive)
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{
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for (uint8_t i = pixelFormat.getProcessColorChannelIndexStart(); i < pixelFormat.getProcessColorChannelIndexEnd(); ++i)
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{
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B_i[i] = PDFBlendFunction::blend(mode, backdropColor[i], sourceColor[i]);
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}
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}
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else
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{
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for (uint8_t i = pixelFormat.getProcessColorChannelIndexStart(); i < pixelFormat.getProcessColorChannelIndexEnd(); ++i)
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{
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B_i[i] = 1.0f - PDFBlendFunction::blend(mode, 1.0f - backdropColor[i], 1.0f - sourceColor[i]);
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}
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}
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}
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if (pixelFormat.hasSpotColors())
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{
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// Blend mode for spot colors must be white-preserving,
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// see 11.7.4.2 of PDF 2.0 specification
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BlendMode spotBlendMode = mode;
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if (!PDFBlendModeInfo::isWhitePreserving(mode))
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{
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spotBlendMode = BlendMode::Normal;
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}
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if (!isSpotColorSubtractive)
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{
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for (uint8_t i = pixelFormat.getSpotColorChannelIndexStart(); i < pixelFormat.getSpotColorChannelIndexEnd(); ++i)
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{
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B_i[i] = PDFBlendFunction::blend(spotBlendMode, backdropColor[i], sourceColor[i]);
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}
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}
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else
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{
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for (uint8_t i = pixelFormat.getSpotColorChannelIndexStart(); i < pixelFormat.getSpotColorChannelIndexEnd(); ++i)
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{
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B_i[i] = 1.0f - PDFBlendFunction::blend(spotBlendMode, 1.0f - backdropColor[i], 1.0f - sourceColor[i]);
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}
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}
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}
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}
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else
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{
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// Nonseparable blend mode - process colors together
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if (pixelFormat.hasProcessColors())
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{
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switch (pixelFormat.getProcessColorChannelCount())
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{
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case 1:
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{
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// Gray
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const PDFGray Cb = backdropColor[pixelFormat.getProcessColorChannelIndexStart()];
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const PDFGray Cs = sourceColor[pixelFormat.getProcessColorChannelIndexStart()];
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const PDFGray blended = PDFBlendFunction::blend_Nonseparable(mode, Cb, Cs);
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B_i[pixelFormat.getProcessColorChannelIndexStart()] = blended;
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break;
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}
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case 3:
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{
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// RGB
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const PDFRGB Cb = { backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 0],
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backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 1],
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backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 2] };
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const PDFRGB Cs = { sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 0],
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sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 1],
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sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 2] };
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const PDFRGB blended = PDFBlendFunction::blend_Nonseparable(mode, Cb, Cs);
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 0] = blended[0];
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 1] = blended[1];
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 2] = blended[2];
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break;
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}
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case 4:
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{
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// CMYK
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const PDFCMYK Cb = { backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 0],
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backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 1],
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backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 2],
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backdropColor[pixelFormat.getProcessColorChannelIndexStart() + 3] };
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const PDFCMYK Cs = { sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 0],
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sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 1],
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sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 2],
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sourceColor[pixelFormat.getProcessColorChannelIndexStart() + 3] };
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const PDFCMYK blended = PDFBlendFunction::blend_Nonseparable(mode, Cb, Cs);
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 0] = blended[0];
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 1] = blended[1];
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 2] = blended[2];
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B_i[pixelFormat.getProcessColorChannelIndexStart() + 3] = blended[3];
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break;
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}
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default:
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{
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// This is a serious error. Blended buffer remains unchanged (zero)
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Q_ASSERT(false);
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break;
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}
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}
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}
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if (pixelFormat.hasSpotColors())
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{
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const bool isSpotColorSubtractive = pixelFormat.hasSpotColorsSubtractive();
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if (!isSpotColorSubtractive)
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{
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for (uint8_t i = pixelFormat.getSpotColorChannelIndexStart(); i < pixelFormat.getSpotColorChannelIndexEnd(); ++i)
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{
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B_i[i] = PDFBlendFunction::blend(BlendMode::Normal, backdropColor[i], sourceColor[i]);
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}
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}
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else
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{
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for (uint8_t i = pixelFormat.getSpotColorChannelIndexStart(); i < pixelFormat.getSpotColorChannelIndexEnd(); ++i)
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{
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B_i[i] = 1.0f - PDFBlendFunction::blend(BlendMode::Normal, 1.0f - backdropColor[i], 1.0f - sourceColor[i]);
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}
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}
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}
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}
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for (uint8_t i = colorChannelStart; i < colorChannelEnd; ++i)
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{
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const PDFColorComponent C_s_i = sourceColor[i];
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const PDFColorComponent C_b = backdropColor[i];
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const PDFColorComponent C_i_1 = targetColor[i];
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PDFColorComponent C_t = (f_s_i - alpha_s_i) * alpha_b * C_b + alpha_s_i * ((1.0f - alpha_b) * C_s_i + alpha_b * B_i[i]);
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PDFColorComponent C_i = ((1.0f - f_s_i) * alpha_i_1 * C_i_1 + C_t) / alpha_i;
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targetColor[i] = C_i;
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}
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targetColor[shapeChannel] = f_g_i;
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targetColor[opacityChannel] = alpha_g_i;
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}
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}
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}
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void PDFFloatBitmap::fillChannel(size_t channel, PDFColorComponent value)
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{
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// Do we have just one channel?
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@ -319,7 +532,58 @@ void PDFTransparencyRenderer::performBeginTransparencyGroup(ProcessOrder order,
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void PDFTransparencyRenderer::performEndTransparencyGroup(ProcessOrder order, const PDFTransparencyGroup& transparencyGroup)
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{
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if (order == ProcessOrder::AfterOperation)
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{
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// "Unblend" the initial backdrop from immediate backdrop, according to 11.4.8
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removeInitialBackdrop();
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PDFTransparencyGroupPainterData sourceData = qMove(m_transparencyGroupDataStack.back());
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m_transparencyGroupDataStack.pop_back();
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PDFTransparencyGroupPainterData& targetData = m_transparencyGroupDataStack.back();
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sourceData.immediateBackdrop.convertToColorSpace(getCMS(), targetData.renderingIntent, targetData.blendColorSpace, this);
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PDFFloatBitmap::blend(sourceData, targetData, *getBackdrop(), *getInitialBackdrop(), sourceData.softMask, sourceData.alphaIsShape, sourceData.alphaFill, BlendMode::Normal);
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}
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}
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void PDFTransparencyRenderer::removeInitialBackdrop()
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{
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PDFFloatBitmapWithColorSpace* immediateBackdrop = getImmediateBackdrop();
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PDFFloatBitmapWithColorSpace* initialBackdrop = getInitialBackdrop();
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PDFPixelFormat pixelFormat = immediateBackdrop->getPixelFormat();
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const uint8_t alphaChannelIndex = pixelFormat.getOpacityChannelIndex();
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const uint8_t colorChannelIndexStart = pixelFormat.getColorChannelIndexStart();
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const uint8_t colorChannelIndexEnd= pixelFormat.getColorChannelIndexEnd();
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Q_ASSERT(alphaChannelIndex != PDFPixelFormat::INVALID_CHANNEL_INDEX);
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Q_ASSERT(colorChannelIndexStart != PDFPixelFormat::INVALID_CHANNEL_INDEX);
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Q_ASSERT(colorChannelIndexEnd != PDFPixelFormat::INVALID_CHANNEL_INDEX);
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for (size_t x = 0; x < immediateBackdrop->getWidth(); ++x)
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{
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for (size_t y = 0; y < immediateBackdrop->getHeight(); ++y)
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{
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PDFColorBuffer initialBackdropColorBuffer = initialBackdrop->getPixel(x, y);
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PDFColorBuffer immediateBackdropColorBuffer = immediateBackdrop->getPixel(x, y);
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const PDFColorComponent alpha_0 = initialBackdropColorBuffer[alphaChannelIndex];
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const PDFColorComponent alpha_g_n = immediateBackdropColorBuffer[alphaChannelIndex];
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if (!qFuzzyIsNull(alpha_g_n))
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{
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for (const uint8_t i = colorChannelIndexStart; i < colorChannelIndexEnd; ++i)
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{
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const PDFColorComponent C_0 = initialBackdropColorBuffer[i];
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const PDFColorComponent C_n = immediateBackdropColorBuffer[i];
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const PDFColorComponent C = C_n + (C_n - C_0) * alpha_0 * (1.0f / alpha_g_n - 1.0f);
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const PDFColorComponent C_clipped = qBound(0.0f, C, 1.0f);
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immediateBackdropColorBuffer[i] = C_clipped;
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}
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}
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}
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}
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}
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PDFFloatBitmapWithColorSpace* PDFTransparencyRenderer::getInitialBackdrop()
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