Add comparation of images with indexed color

Previously, two images with indexed colors were not equal if their
color tables were not the same. The image are not compared by
the value of the pixels

Reviewed-by: Samuel

2 files changed, 33 insertions, 5 deletions

diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index 25c68bc..c1c5631 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -4853,8 +4853,6 @@ bool QImage::operator==(const QImage & i) const
         return false;
 
     if (d->format != Format_RGB32) {
-        if (d->colortable != i.d->colortable)
-            return false;
         if (d->format >= Format_ARGB32) { // all bits defined
             const int n = d->width * d->depth / 8;
             if (n == d->bytes_per_line && n == i.d->bytes_per_line) {
@@ -4867,11 +4865,13 @@ bool QImage::operator==(const QImage & i) const
                 }
             }
         } else {
-            int w = width();
-            int h = height();
+            const int w = width();
+            const int h = height();
+            const QVector<QRgb> &colortable = d->colortable;
+            const QVector<QRgb> &icolortable = i.d->colortable;
             for (int y=0; y<h; ++y) {
                 for (int x=0; x<w; ++x) {
-                    if (pixelIndex(x, y) != i.pixelIndex(x, y))
+                    if (colortable[pixelIndex(x, y)] != icolortable[i.pixelIndex(x, y)])
                         return false;
                 }
             }
diff --git a/tests/auto/qimage/tst_qimage.cpp b/tests/auto/qimage/tst_qimage.cpp
index c6b0560..b7199f3 100644
--- a/tests/auto/qimage/tst_qimage.cpp
+++ b/tests/auto/qimage/tst_qimage.cpp
@@ -131,6 +131,8 @@ private slots:
     void nullSize();
 
     void premultipliedAlphaConsistency();
+
+    void compareIndexed();
 };
 
 tst_QImage::tst_QImage()
@@ -1762,5 +1764,31 @@ void tst_QImage::premultipliedAlphaConsistency()
     }
 }
 
+void tst_QImage::compareIndexed()
+{
+    QImage img(256, 1, QImage::Format_Indexed8);
+
+    QVector<QRgb> colorTable(256);
+    for (int i = 0; i < 256; ++i)
+        colorTable[i] = qRgb(i, i, i);
+    img.setColorTable(colorTable);
+
+    for (int i = 0; i < 256; ++i) {
+        img.setPixel(i, 0, i);
+    }
+
+    QImage imgInverted(256, 1, QImage::Format_Indexed8);
+    QVector<QRgb> invertedColorTable(256);
+    for (int i = 0; i < 256; ++i)
+        invertedColorTable[255-i] = qRgb(i, i, i);
+    imgInverted.setColorTable(invertedColorTable);
+
+    for (int i = 0; i < 256; ++i) {
+        imgInverted.setPixel(i, 0, (255-i));
+    }
+
+    QCOMPARE(img, imgInverted);
+}
+
 QTEST_MAIN(tst_QImage)
 #include "tst_qimage.moc"