[vlc-commits] [Git][videolan/vlc][master] qml: do not let qt to create implicit layer in artist top banner

[Steve Lhomme (@robUx4)]

Steve Lhomme pushed to branch master at VideoLAN / VLC


Commits:
b19ddcc9 by Fatih Uzunoglu at 2025-02-02T10:18:44+00:00
qml: do not let qt to create implicit layer in artist top banner

Here, Qt wants to create a layer because when source is `QQuickImage`,
`QGfxSourceProxy(ME)` checks its fill mode and source size.

In this case, we need to tell Qt that we don't need a layer here, as
we are doing the mapping as we want but Qt currently does not offer
a way to tell that and simply tries to decide itself: "If needed,
MultiEffect will internally generate a ShaderEffectSource as the
texture source"

Using the static texture for the blur source has also the advantage
of applying blur only once because the source would not get updated
constantly due to size change. With clipping, we can simply adjust
the viewport without needing to update the blur.

Unfortunately we can not do this with older Qt versions, because if
the source image changes fill mode from stretch or to stretch where
it is fed to a blur effect, the effect either causes crash (layering
needed to not needed, so Tile -> Stretch) or does not work (layering
not needed to needed, so Stretch -> Tile).

- - - - -


1 changed file:

- modules/gui/qt/medialibrary/qml/ArtistTopBanner.qml


Changes:

=====================================
modules/gui/qt/medialibrary/qml/ArtistTopBanner.qml
=====================================
@@ -62,7 +62,18 @@ FocusScope {
         sourceSize: artist.cover ? Qt.size(Helpers.alignUp(Screen.desktopAvailableWidth, 32), 0)
                                  : undefined
         mipmap: !!artist.cover
-        fillMode: artist.cover ? Image.PreserveAspectCrop : Image.Tile
+        // Fill mode is stretch when blur effect is used, otherwise an implicit layer is created.
+        // Having the fill mode stretch does not have a side effect here, because source size
+        // is still calculated as to preserve the aspect ratio as height is left empty (0) and the
+        // image is not shown stretched because it is invisible when blur effect is used:
+        // "If only one dimension of the size is set to greater than 0, the other dimension is
+        //  set in proportion to preserve the source image's aspect ratio. (The fillMode is
+        //  independent of this.)". Unfortunately with old Qt versions we can not do this
+        // because it does not seem to create a layer when fill mode (tiling is wanted)
+        // is changed at a later point.
+        fillMode: artist.cover ? ((visible || (MainCtx.qtVersion() < MainCtx.qtVersionCheck(6, 5, 0))) ? Image.PreserveAspectCrop : Image.Stretch)
+                                : Image.Tile
+
         visible: layer.enabled
         cache: (source === VLCStyle.noArtArtist)
 
@@ -72,10 +83,42 @@ FocusScope {
         layer.textureSize: Qt.size(width * .75, height * .75)
     }
 
-    Widgets.BlurEffect {
+    Item {
         anchors.fill: background
-        source: background
-        radius: VLCStyle.dp(4, VLCStyle.scale)
+
+        // The texture is big, and the blur item should only draw the portion of it.
+        // If the blur effect creates an implicit layer, it properly adjusts the
+        // area that it needs to cover. However, as we don't want an additional
+        // layer that keeps getting updated every time the size changes, we feed
+        // the whole static texture. For that reason, we need clipping because
+        // the blur effect is applied to the whole texture and shown as whole:
+        clip: !blurEffect.sourceNeedsLayering
+
+        visible: !background.visible && (GraphicsInfo.shaderType === GraphicsInfo.RhiShader)
+
+        // This blur effect does not create an implicit layer that is updated
+        // each time the size changes. The source texture is static, so the blur
+        // is applied only once and we adjust the viewport through the parent item
+        // with clipping.
+        Widgets.BlurEffect {
+            id: blurEffect
+
+            anchors.verticalCenter: parent.verticalCenter
+            anchors.left: parent.left
+            anchors.right: parent.right
+
+            // If source image is tiled, layering is necessary:
+            readonly property bool sourceNeedsLayering: (background.fillMode !== Image.Stretch) ||
+                                                        (MainCtx.qtVersion() < MainCtx.qtVersionCheck(6, 5, 0))
+
+            readonly property real aspectRatio: (background.implicitHeight / background.implicitWidth)
+
+            height: sourceNeedsLayering ? background.height : (aspectRatio * width)
+
+            source: background
+
+            radius: VLCStyle.dp(4, VLCStyle.scale)
+        }
     }
 
     Rectangle {



View it on GitLab: https://code.videolan.org/videolan/vlc/-/commit/b19ddcc9d25416295d43bf5e91e9e8c04f94ee33

-- 
View it on GitLab: https://code.videolan.org/videolan/vlc/-/commit/b19ddcc9d25416295d43bf5e91e9e8c04f94ee33
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