Display of ink coverage

Pdf4QtLib/sources/pdftransparencyrenderer.cpp

@@ -90,6 +90,23 @@ PDFColorComponent PDFFloatBitmap::getPixelInkCoverage(size_t x, size_t y) const
     return inkCoverage;
 }
 
+PDFFloatBitmap PDFFloatBitmap::getInkCoverageBitmap() const
+{
+    PDFFloatBitmap result(getWidth(), getHeight(), PDFPixelFormat::createFormat(1, 0, false, true, false));
+
+    for (size_t y = 0; y < getHeight(); ++y)
+    {
+        for (size_t x = 0; x < getWidth(); ++x)
+        {
+            PDFColorComponent coverage = getPixelInkCoverage(x, y);
+            PDFColorBuffer targetProcessColorBuffer = result.getPixel(x, y);
+            targetProcessColorBuffer[0] = coverage;
+        }
+    }
+
+    return result;
+}
+
 const PDFColorComponent* PDFFloatBitmap::begin() const
 {
     return m_data.data();

Pdf4QtLib/sources/pdftransparencyrenderer.h

@@ -160,6 +160,10 @@ public:
     /// Returns ink coverage
     PDFColorComponent getPixelInkCoverage(size_t x, size_t y) const;
 
+    /// Returns ink coverage bitmap. Bitmap consists of one color channel,
+    /// which consists of ink coverage.
+    PDFFloatBitmap getInkCoverageBitmap() const;
+
     const PDFColorComponent* begin() const;
     const PDFColorComponent* end() const;
 

Pdf4QtLib/sources/pdfutils.cpp

@@ -518,4 +518,43 @@ QString PDFSysUtils::getUserName()
     return userName;
 }
 
+PDFColorScale::PDFColorScale(PDFReal min, PDFReal max) :
+    m_min(min),
+    m_max(max)
+{
+    m_colorScales = {
+        Qt::blue,
+        Qt::cyan,
+        Qt::green,
+        Qt::yellow,
+        Qt::red
+    };
+}
+
+QColor PDFColorScale::map(PDFReal value) const
+{
+    PDFReal correctedValue = qBound(m_min, value, m_max);
+    PDFReal intervalValue = interpolate(correctedValue, m_min, m_max, 0.0, PDFReal(m_colorScales.size() - 1));
+    PDFReal indexValue = qFloor(intervalValue);
+    int index = indexValue;
+    PDFReal fractionValue = intervalValue - index;
+
+    if (index == int(m_colorScales.size()) - 1)
+    {
+        --index;
+        fractionValue = 1.0;
+    }
+
+    Q_ASSERT(index + 1 < m_colorScales.size());
+
+    const QColor& leftValue = m_colorScales[index];
+    const QColor& rightValue = m_colorScales[index + 1];
+
+    qreal r = (1.0 - fractionValue) * leftValue.redF() + fractionValue * rightValue.redF();
+    qreal g = (1.0 - fractionValue) * leftValue.greenF() + fractionValue * rightValue.greenF();
+    qreal b = (1.0 - fractionValue) * leftValue.blueF() + fractionValue * rightValue.blueF();
+
+    return QColor::fromRgbF(r, g, b);
+}
+
 }   // namespace pdf

Pdf4QtLib/sources/pdfutils.h

@@ -806,6 +806,21 @@ QDataStream& operator<<(QDataStream& stream, const std::set<T>& set)
     return stream;
 }
 
+/// Color scale represents hot-to-cold color scale. It maps value
+/// to the color from blue trough green to red.
+class Pdf4QtLIBSHARED_EXPORT PDFColorScale
+{
+public:
+    explicit PDFColorScale(PDFReal min, PDFReal max);
+
+    QColor map(PDFReal value) const;
+
+private:
+    std::vector<QColor> m_colorScales;
+    PDFReal m_min;
+    PDFReal m_max;
+};
+
 }   // namespace pdf
 
 #endif // PDFUTILS_H