Apply identity transforms if they adjust the image

Transforms now get applied properly if the opacity or blend mode is the
only thing that is changed. Previously they would end up not doing
anything because the identity transform caused the code path to bail out
early.

ChangeLog

@@ -83,6 +83,7 @@ Unreleased Version 2.2.2-pre
  * Feature: Allow selecting and then moving, grouping, deleting etc. of multiple layers at once. To select multiple layers, hold Shift or Ctrl while making a selection or use the boxes on the right. Thanks MorrowShore for suggesting parts of this.
  * Feature: Allow dragging across the layer icons to hide the visibility of multiple layers in a row, rather than having to click each one. Thanks MorrowShore for suggesting.
  * Feature: The fill and magic wand tools now always at least fill the initial pixel if gap closing or shrinking would up with a blank result. Thanks MorrowShore for suggesting.
+ * Fix: Properly apply transforms if the only thing you change is the opacity or blend mode. Thanks Blozzom for reporting.
 
 2024-11-06 Version 2.2.2-beta.4
  * Fix: Solve rendering glitches with selection outlines that happen on some systems. Thanks xxxx for reporting.

src/libclient/canvas/transformmodel.cpp

@@ -262,9 +262,11 @@ QVector<net::Message> TransformModel::applyFromCanvas(
 	Q_ASSERT(m_active);
 	Q_ASSERT(!m_pasted || m_stamped);
 	bool identity = TransformQuad(m_srcBounds) == m_dstQuad;
+	bool adjustsImage =
+		m_blendMode != int(DP_BLEND_MODE_NORMAL) || m_opacity < 1.0;
 	int singleLayerSourceId =
 		compatibilityMode ? 0 : getSingleLayerMoveId(layerId);
-	if(!identity ||
+	if(!identity || adjustsImage ||
 	   (singleLayerSourceId > 0 && singleLayerSourceId != layerId)) {
 		int srcX = m_srcBounds.x();
 		int srcY = m_srcBounds.y();
@@ -277,8 +279,6 @@ QVector<net::Message> TransformModel::applyFromCanvas(
 		bool moveSelection = alterSelection && !m_deselectOnApply;
 		bool needsMask = moveContents && !m_mask.isNull();
 		bool sizeOutOfBounds = isDstQuadBoundingRectAreaSizeOutOfBounds();
-		bool adjustsImage =
-			m_blendMode != int(DP_BLEND_MODE_NORMAL) || m_opacity < 1.0;
 		QVector<net::Message> msgs;
 		msgs.reserve(1 + (moveContents ? 1 : 0) + (alterSelection ? 1 : 0));