Add an example to the documentation of QImage::scanLine()

I couldn't find any examples in Qt's documentation of this when I was
trying to use it in a project.

Pick-to: 5.15 5.12
Change-Id: Ic7b7b71f219b2c1012829980866940b9a77bd11f
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/gui/doc/snippets/code/src_gui_image_qimage.cpp b/src/gui/doc/snippets/code/src_gui_image_qimage.cpp
index b36d12018a..cbc2aaae33 100644
--- a/src/gui/doc/snippets/code/src_gui_image_qimage.cpp
+++ b/src/gui/doc/snippets/code/src_gui_image_qimage.cpp
@@ -99,6 +99,17 @@ static const char * const start_xpm[] = {
 };
 //! [2]
 
+
+//! [scanLine]
+for (int y = 0; y < image.height(); ++y) {
+    QRgb *line = reinterpret_cast<QRgb*>(image.scanLine(y));
+    for (int x = 0; x < image.width(); ++x) {
+        QRgb &rgb = line[x];
+        rgb = qRgba(qRed(rgb), qGreen(0), qBlue(rgb), qAlpha(rgb));
+    }
+}
+//! [scanLine]
+
 Q_UNUSED(start_xpm);
 } // wrapper1
 } // src_gui_image_qimage