From a8d702ba306d2dabfc95368ca7c0facd445592ff Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Fri, 28 May 2021 11:13:56 +0300
Subject: [PATCH] effects/screenshot: Port away from window quads

For the scene redesign, window quads need to be removed from the effects
api. This change ports the screenshot effect away from quads.

In order to exclude the server-side decoration from the window
screenshot, the effect will render the contents of the client geometry
into the offscreen texture. If the window is client-side decorated, the
entire window will be rendered as before.

The good thing about this approach is that the screenshot effect will do
less work, it won't loop over window quads to compute the bounding rect
or filter out the deco quads.
---
 src/effects/screenshot/screenshot.cpp | 54 +++++++--------------------
 1 file changed, 14 insertions(+), 40 deletions(-)

diff --git a/src/effects/screenshot/screenshot.cpp b/src/effects/screenshot/screenshot.cpp
index f2d77aad89..ee6d985c5f 100644
--- a/src/effects/screenshot/screenshot.cpp
+++ b/src/effects/screenshot/screenshot.cpp
@@ -238,50 +238,23 @@ void ScreenShotEffect::takeScreenShot(ScreenShotWindowData *screenshot)
     EffectWindow *window = screenshot->window;
 
     WindowPaintData d(window);
-    double left = 0;
-    double top = 0;
-    double right = window->width();
-    double bottom = window->height();
-    if (window->hasDecoration() && (screenshot->flags & ScreenShotIncludeDecoration)) {
-        for (const WindowQuad &quad : qAsConst(d.quads)) {
-            // we need this loop to include the decoration padding
-            left = qMin(left, quad.left());
-            top = qMin(top, quad.top());
-            right = qMax(right, quad.right());
-            bottom = qMax(bottom, quad.bottom());
-        }
-    } else if (window->hasDecoration()) {
-        WindowQuadList newQuads;
-        left = window->width();
-        top = window->height();
-        right = 0;
-        bottom = 0;
-        for (const WindowQuad &quad : qAsConst(d.quads)) {
-            if (quad.type() == WindowQuadContents) {
-                newQuads << quad;
-                left = qMin(left, quad.left());
-                top = qMin(top, quad.top());
-                right = qMax(right, quad.right());
-                bottom = qMax(bottom, quad.bottom());
-            }
-        }
-        d.quads = newQuads;
+    QRect geometry = window->expandedGeometry();
+    if (window->hasDecoration() && !(screenshot->flags & ScreenShotIncludeDecoration)) {
+        geometry = window->clientGeometry();
     }
-    const int width = right - left;
-    const int height = bottom - top;
     bool validTarget = true;
     QScopedPointer<GLTexture> offscreenTexture;
     QScopedPointer<GLRenderTarget> target;
     if (effects->isOpenGLCompositing()) {
-        offscreenTexture.reset(new GLTexture(GL_RGBA8, width, height));
+        offscreenTexture.reset(new GLTexture(GL_RGBA8, geometry.size()));
         offscreenTexture->setFilter(GL_LINEAR);
         offscreenTexture->setWrapMode(GL_CLAMP_TO_EDGE);
         target.reset(new GLRenderTarget(*offscreenTexture));
         validTarget = target->valid();
     }
     if (validTarget) {
-        d.setXTranslation(-window->x() - left);
-        d.setYTranslation(-window->y() - top);
+        d.setXTranslation(-geometry.x());
+        d.setYTranslation(-geometry.y());
 
         // render window into offscreen texture
         int mask = PAINT_WINDOW_TRANSFORMED | PAINT_WINDOW_TRANSLUCENT;
@@ -293,31 +266,32 @@ void ScreenShotEffect::takeScreenShot(ScreenShotWindowData *screenshot)
             glClearColor(0.0, 0.0, 0.0, 1.0);
 
             QMatrix4x4 projection;
-            projection.ortho(QRect(0, 0, offscreenTexture->width(), offscreenTexture->height()));
+            projection.ortho(QRect(0, 0, geometry.width(), geometry.height()));
             d.setProjectionMatrix(projection);
 
             effects->drawWindow(window, mask, infiniteRegion(), d);
 
             // copy content from framebuffer into image
-            img = QImage(QSize(width, height), QImage::Format_ARGB32);
-            glReadnPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, img.sizeInBytes(),
+            img = QImage(offscreenTexture->size(), QImage::Format_ARGB32);
+            glReadnPixels(0, 0, img.width(), img.height(), GL_RGBA, GL_UNSIGNED_BYTE, img.sizeInBytes(),
                           static_cast<GLvoid *>(img.bits()));
             GLRenderTarget::popRenderTarget();
-            convertFromGLImage(img, width, height);
+            convertFromGLImage(img, img.width(), img.height());
         }
 #if defined(KWIN_HAVE_XRENDER_COMPOSITING)
         if (effects->compositingType() == XRenderCompositing) {
             setXRenderOffscreen(true);
-            effects->drawWindow(window, mask, QRegion(0, 0, width, height), d);
+            effects->drawWindow(window, mask, QRegion(0, 0, geometry.width(), geometry.height()), d);
             if (xRenderOffscreenTarget()) {
-                img = xPictureToImage(xRenderOffscreenTarget(), QRect(0, 0, width, height));
+                img = xPictureToImage(xRenderOffscreenTarget(),
+                                      QRect(0, 0, geometry.width(), geometry.height()));
             }
             setXRenderOffscreen(false);
         }
 #endif
 
         if (screenshot->flags & ScreenShotIncludeCursor) {
-            grabPointerImage(img, window->x() + left, window->y() + top);
+            grabPointerImage(img, geometry.x(), geometry.y());
         }
 
         screenshot->promise.reportResult(img);