Avoid image conversion in fromSymbianCFbsBitmap for certain formats.

From now on the image data coming from CFbsBitmap will not be forced
to RGB32 or ARGB32_Premultiplied in openvg. This allows copy-less
creation and drawing of pixmaps not just from bitmaps with display mode
EColor16MAP and EColor16MU, but also a few other modes, like EColor64K.
Painting into such pixmaps or drawing them via the raster engine is
potentially slower in such cases, which is now reflected in the
fromSymbianCFbsBitmap documentation.
Note that this patch has no effect on extended bitmaps (e.g. skin
graphics), those must always be rasterized first regardless of the
display mode.

Task-number: QTBUG-18027
Reviewed-by: Jani Hautakangas

1 files changed, 20 insertions, 3 deletions

diff --git a/src/openvg/qvg_symbian.cpp b/src/openvg/qvg_symbian.cpp
index 5eb64bd..405151d 100644
--- a/src/openvg/qvg_symbian.cpp
+++ b/src/openvg/qvg_symbian.cpp
@@ -150,6 +150,21 @@ void QVGPixmapData::releaseNativeImageHandle()
     }
 }
 
+static inline bool conversionLessFormat(QImage::Format format)
+{
+    switch (format) {
+        case QImage::Format_RGB16: // EColor64K
+        case QImage::Format_RGB32: // EColor16MU
+        case QImage::Format_ARGB32: // EColor16MA
+        case QImage::Format_ARGB32_Premultiplied: // EColor16MAP
+        case QImage::Format_MonoLSB: // EGray2
+        case QImage::Format_Indexed8: // EGray256, EColor256
+            return true;
+        default:
+            return false;
+    }
+}
+
 void QVGPixmapData::fromNativeType(void* pixmap, NativeType type)
 {
     if (type == QPixmapData::SgImage && pixmap) {
@@ -178,9 +193,11 @@ void QVGPixmapData::fromNativeType(void* pixmap, NativeType type)
         source = QVolatileImage(bitmap); // duplicates only, if possible
         if (source.isNull())
             return;
-        // Here we may need to copy if the formats do not match.
-        // (e.g. for display modes other than EColor16MAP and EColor16MU)
-        source.ensureFormat(idealFormat(&source.imageRef(), Qt::AutoColor));
+        if (!conversionLessFormat(source.format())) {
+            // Here we may need to copy if the formats do not match.
+            // (e.g. for display modes other than EColor16MAP and EColor16MU)
+            source.ensureFormat(idealFormat(&source.imageRef(), Qt::AutoColor));
+        }
         recreate = true;
     } else if (type == QPixmapData::VolatileImage && pixmap) {
         QVolatileImage *img = static_cast<QVolatileImage *>(pixmap);