From d12112b7a569ad8094d3e3c8d3c3087b07a6220c Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Sun, 11 Aug 2024 19:54:22 +0300
Subject: [PATCH] scene: Make ImageItem provide device texture coordinates

The main motivation behind this change is to make the ItemRendererOpenGL
use a homogeneous coordinate space for texture coordinates in order to
simplify rendering code.

The device pixels have been chosen because they are more agnostic about
the graphics api.
---
 src/scene/imageitem.cpp           | 11 +++++++----
 src/scene/itemrenderer_opengl.cpp |  2 +-
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/scene/imageitem.cpp b/src/scene/imageitem.cpp
index 72df2ccc94..ea669ad3da 100644
--- a/src/scene/imageitem.cpp
+++ b/src/scene/imageitem.cpp
@@ -24,6 +24,7 @@ QImage ImageItem::image() const
 void ImageItem::setImage(const QImage &image)
 {
     m_image = image;
+    discardQuads();
 }
 
 ImageItemOpenGL::ImageItemOpenGL(Item *parent)
@@ -68,11 +69,13 @@ WindowQuadList ImageItemOpenGL::buildQuads() const
         return WindowQuadList{};
     }
 
+    const QRectF imageRect = m_image.rect();
+
     WindowQuad quad;
-    quad[0] = WindowVertex(geometry.topLeft(), QPointF(0, 0));
-    quad[1] = WindowVertex(geometry.topRight(), QPointF(1, 0));
-    quad[2] = WindowVertex(geometry.bottomRight(), QPointF(1, 1));
-    quad[3] = WindowVertex(geometry.bottomLeft(), QPointF(0, 1));
+    quad[0] = WindowVertex(geometry.topLeft(), imageRect.topLeft());
+    quad[1] = WindowVertex(geometry.topRight(), imageRect.topRight());
+    quad[2] = WindowVertex(geometry.bottomRight(), imageRect.bottomRight());
+    quad[3] = WindowVertex(geometry.bottomLeft(), imageRect.bottomLeft());
 
     WindowQuadList ret;
     ret.append(quad);
diff --git a/src/scene/itemrenderer_opengl.cpp b/src/scene/itemrenderer_opengl.cpp
index 94dbcbba6c..01105abe8c 100644
--- a/src/scene/itemrenderer_opengl.cpp
+++ b/src/scene/itemrenderer_opengl.cpp
@@ -210,7 +210,7 @@ void ItemRendererOpenGL::createRenderNode(Item *item, RenderContext *context)
                 .transformMatrix = context->transformStack.top(),
                 .opacity = context->opacityStack.top(),
                 .hasAlpha = imageItem->image().hasAlphaChannel(),
-                .coordinateType = NormalizedCoordinates,
+                .coordinateType = UnnormalizedCoordinates,
                 .colorDescription = item->colorDescription(),
                 .renderingIntent = item->renderingIntent(),
                 .bufferReleasePoint = nullptr,