port of EQL/Qt4 to Qt5

examples/X-extras/cpp-qimage/lib.cpp

@@ -0,0 +1,31 @@
+#include "lib.h"
+
+QT_BEGIN_NAMESPACE
+
+QObject* ini() {
+    static CPP* cpp = 0;
+    if(!cpp) {
+        cpp = new CPP; }
+    return cpp; }
+
+static void _toGrayscale(QImage* image) { 
+    if(image) {
+        // stolen from Stack Overflow
+        for(int y = 0; y < image->height(); y++) {
+            uchar* scan = image->scanLine(y);
+            int depth = 4;
+            for(int x = 0; x < image->width(); x++) {
+                QRgb* rgbpixel = reinterpret_cast<QRgb*>(scan + x * depth);
+                int gray = qGray(*rgbpixel);
+                *rgbpixel = QColor(gray, gray, gray).rgba(); }}}}
+
+QImage CPP::toGrayscale(const QImage& image) { 
+    QImage image2 = image;
+    image2.detach();
+    _toGrayscale(&image2);
+    return image2; }
+
+void CPP::toGrayscaleReplace(QImage* image) { 
+    _toGrayscale(image); }
+
+QT_END_NAMESPACE