Premultiply the color table instead of each pixel for image conversion

When converting indexed images in place, each color was converted to
premultiplied. Instead, we can just convert the color table like it
is done in the non-in-place version.

Reviewed-by: Kim

1 files changed, 7 insertions, 2 deletions

diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index e5930ac..e8c01c7 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -2343,6 +2343,9 @@ static bool convert_indexed8_to_ARGB_PM_inplace(QImageData *data, Qt::ImageConve
         data->colortable.resize(256);
         for (int i = 0; i < 256; ++i)
             data->colortable[i] = qRgb(i, i, i);
+    } else {
+        for (int i = 0; i < data->colortable.size(); ++i)
+            data->colortable[i] = PREMUL(data->colortable.at(i));
     }
     const int tableSize = data->colortable.size() - 1;
 
@@ -2352,11 +2355,11 @@ static bool convert_indexed8_to_ARGB_PM_inplace(QImageData *data, Qt::ImageConve
         for (int pixI = 0; pixI < width; ++pixI) {
             --src_data;
             --dest_data;
-            const uint pixel = data->colortable[qMin<int>(tableSize, *src_data)];
-            *dest_data = (quint32) PREMUL(pixel);
+            *dest_data = data->colortable[qMin<int>(tableSize, *src_data)];
         }
     }
 
+    data->colortable = QVector<QRgb>();
     data->format = QImage::Format_ARGB32_Premultiplied;
     data->bytes_per_line = dst_bytes_per_line;
     data->depth = depth;
@@ -2401,6 +2404,7 @@ static bool convert_indexed8_to_RGB_inplace(QImageData *data, Qt::ImageConversio
         }
     }
 
+    data->colortable = QVector<QRgb>();
     data->format = QImage::Format_RGB32;
     data->bytes_per_line = dst_bytes_per_line;
     data->depth = depth;
@@ -2446,6 +2450,7 @@ static bool convert_indexed8_to_RGB16_inplace(QImageData *data, Qt::ImageConvers
         }
     }
 
+    data->colortable = QVector<QRgb>();
     data->format = QImage::Format_RGB16;
     data->bytes_per_line = dst_bytes_per_line;
     data->depth = depth;