From a2b056d45682b16941ffff3ac99cc97815843d28 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jaakko=20Kera=CC=88nen?= <jaakko.keranen@iki.fi>
Date: Thu, 5 Apr 2018 22:20:11 +0300
Subject: [PATCH] libgui|Image: Added more image manipulation methods

---
 doomsday/libs/gui/include/de/graphics/image.h | 11 +++
 doomsday/libs/gui/src/graphics/image.cpp      | 71 ++++++++++++++++++-
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/doomsday/libs/gui/include/de/graphics/image.h b/doomsday/libs/gui/include/de/graphics/image.h
index bb37679621..b333e5769a 100644
--- a/doomsday/libs/gui/include/de/graphics/image.h
+++ b/doomsday/libs/gui/include/de/graphics/image.h
@@ -93,6 +93,14 @@ class LIBGUI_PUBLIC Image : public ISerializable
     Image(Image const &other);
     Image(QImage const &image);
 
+    /**
+     * Constructs an image with uninitialized contents.
+     *
+     * @param size    Size of the image.
+     * @param format  Data format.
+     */
+    Image(Size const &size, Format format);
+
     /**
      * Constructs an image, taking a copy of the pixel data.
      *
@@ -180,6 +188,9 @@ class LIBGUI_PUBLIC Image : public ISerializable
     Image multiplied(Image const &factorImage) const;
     Image multiplied(Color const &color) const;
     Image colorized(Color const &color) const;
+    Image invertedColor() const;
+    Image mixed(Image const &low, Image const &high) const;
+    Image withAlpha(Image const &grayscale) const;
 
     // Implements ISerializable.
     void operator >> (Writer &to) const;
diff --git a/doomsday/libs/gui/src/graphics/image.cpp b/doomsday/libs/gui/src/graphics/image.cpp
index 511325c50f..671d4919e5 100644
--- a/doomsday/libs/gui/src/graphics/image.cpp
+++ b/doomsday/libs/gui/src/graphics/image.cpp
@@ -346,7 +346,7 @@ DENG2_PIMPL(Image)
         size = Size(img.width(), img.height());
     }
 
-    Impl(Public * i, Impl const &other)
+    Impl(Public *i, Impl const &other)
         : Base(i)
         , format(other.format)
         , size(other.size)
@@ -356,6 +356,12 @@ DENG2_PIMPL(Image)
         , pointRatio(other.pointRatio)
     {}
 
+    Impl(Public *i, Size const &imgSize, Format imgFormat)
+        : Base(i), format(imgFormat), size(imgSize)
+    {
+        pixels.resize(i->stride() * imgSize.y);
+    }
+
     Impl(Public *i, Size const &imgSize, Format imgFormat, IByteArray const &imgPixels)
         : Base(i), format(imgFormat), size(imgSize), pixels(imgPixels)
     {}
@@ -375,6 +381,10 @@ Image::Image(Image const &other)
 Image::Image(QImage const &image) : d(new Impl(this, image))
 {}
 
+Image::Image(Size const &size, Format format)
+    : d(new Impl(this, size, format))
+{}
+
 Image::Image(Size const &size, Format format, IByteArray const &pixels)
     : d(new Impl(this, size, format, pixels))
 {}
@@ -734,6 +744,65 @@ Image Image::colorized(Color const &color) const
     return copy;
 }
 
+Image Image::invertedColor() const
+{
+    QImage img = toQImage().convertToFormat(QImage::Format_ARGB32);
+    img.invertPixels();
+    return img;
+}
+
+Image Image::mixed(Image const &low, Image const &high) const
+{
+    DENG2_ASSERT(size() == low.size());
+    DENG2_ASSERT(size() == high.size());
+
+    const QImage lowImg  = low.toQImage();
+    const QImage highImg = high.toQImage();
+
+    QImage mix = toQImage().convertToFormat(QImage::Format_ARGB32);
+    for (duint y = 0; y < height(); ++y)
+    {
+        duint32 *ptr = reinterpret_cast<duint32 *>(mix.bits() + y * mix.bytesPerLine());
+        for (duint x = 0; x < width(); ++x)
+        {
+            duint mb =  *ptr & 0xff;
+            duint mg = (*ptr & 0xff00) >> 8;
+            duint mr = (*ptr & 0xff0000) >> 16;
+            duint ma = (*ptr & 0xff000000) >> 24;
+
+            const QRgb lowColor  = lowImg .pixel(x, y);
+            const QRgb highColor = highImg.pixel(x, y);
+
+            int red   = (qRed(highColor)   * mr + qRed(lowColor)   * (255 - mr)) / 255;
+            int green = (qGreen(highColor) * mg + qGreen(lowColor) * (255 - mg)) / 255;
+            int blue  = (qBlue(highColor)  * mb + qBlue(lowColor)  * (255 - mb)) / 255;
+            int alpha = (qAlpha(highColor) * ma + qAlpha(lowColor) * (255 - ma)) / 255;
+
+            *ptr = blue | (green << 8) | (red << 16) | (alpha << 24);
+
+            ptr++;
+        }
+    }
+    return mix;
+}
+
+Image Image::withAlpha(Image const &grayscale) const
+{
+    DENG2_ASSERT(size() == grayscale.size());
+    const QImage alpha = grayscale.toQImage();
+    QImage img = toQImage().convertToFormat(QImage::Format_ARGB32);
+    for (duint y = 0; y < height(); ++y)
+    {
+        duint32 *ptr = reinterpret_cast<duint32 *>(img.bits() + y * img.bytesPerLine());
+        for (duint x = 0; x < width(); ++x)
+        {
+            *ptr &= 0x00ffffff;
+            *ptr++ |= qRed(alpha.pixel(x, y)) << 24;
+        }
+    }
+    return img;
+}
+
 void Image::operator >> (Writer &to) const
 {
     to << duint8(d->format);