Make Item::grabToImage work in more cases, and improve test coverage

This fixes a regression caused by 9c50216c7bbbdb2bb51d4485286bf09e12fb5b62
when the Image specified fillMode: aspectRatioCrop/Fit.

[ChangeLog][QtQuick][Image] Item::grabToImage on an Image element will now work
regardless of the Image's sourceSize or cache properties.

Change-Id: I225854c48f0c35a3cb2ef0dd56bf51bd88c31779
Reviewed-by: Robin Burchell <robin.burchell@crimson.no>

4 files changed, 50 insertions, 7 deletions

diff --git a/src/quick/items/qquickitemgrabresult.cpp b/src/quick/items/qquickitemgrabresult.cpp
index 07c2cb607c..12bcd43076 100644
--- a/src/quick/items/qquickitemgrabresult.cpp
+++ b/src/quick/items/qquickitemgrabresult.cpp
@@ -75,7 +75,7 @@ public:
 
     void ensureImageInCache() const {
         if (url.isEmpty() && !image.isNull()) {
-            url.setScheme(QStringLiteral("ItemGrabber"));
+            url.setScheme(QQuickPixmap::itemGrabberScheme);
             url.setPath(QVariant::fromValue(item.data()).toString());
             static uint counter = 0;
             url.setFragment(QString::number(++counter));
diff --git a/src/quick/util/qquickpixmapcache.cpp b/src/quick/util/qquickpixmapcache.cpp
index 1c6b2afb54..be6d4d18bd 100644
--- a/src/quick/util/qquickpixmapcache.cpp
+++ b/src/quick/util/qquickpixmapcache.cpp
@@ -84,6 +84,7 @@
 
 QT_BEGIN_NAMESPACE
 
+const QLatin1String QQuickPixmap::itemGrabberScheme = QLatin1String("itemgrabber");
 
 #ifndef QT_NO_DEBUG
 static const bool qsg_leak_check = !qEnvironmentVariableIsEmpty("QML_LEAK_CHECK");
@@ -1462,8 +1463,15 @@ void QQuickPixmap::load(QQmlEngine *engine, const QUrl &url, const QSize &reques
     QHash<QQuickPixmapKey, QQuickPixmapData *>::Iterator iter = store->m_cache.end();
 
     // If Cache is disabled, the pixmap will always be loaded, even if there is an existing
-    // cached version.
-    if (options & QQuickPixmap::Cache)
+    // cached version. Unless it's an itemgrabber url, since the cache is used to pass
+    // the result between QQuickItemGrabResult and QQuickImage.
+    if (url.scheme() == itemGrabberScheme) {
+        QSize dummy;
+        if (requestSize != dummy)
+            qWarning() << "Ignoring sourceSize request for image url that came from grabToImage. Use the targetSize parameter of the grabToImage() function instead.";
+        const QQuickPixmapKey grabberKey = { &url, &dummy, QQuickImageProviderOptions() };
+        iter = store->m_cache.find(grabberKey);
+    } else if (options & QQuickPixmap::Cache)
         iter = store->m_cache.find(key);
 
     if (iter == store->m_cache.end()) {
diff --git a/src/quick/util/qquickpixmapcache_p.h b/src/quick/util/qquickpixmapcache_p.h
index f7cdfa7d07..a867771755 100644
--- a/src/quick/util/qquickpixmapcache_p.h
+++ b/src/quick/util/qquickpixmapcache_p.h
@@ -177,6 +177,8 @@ public:
     static void purgeCache();
     static bool isCached(const QUrl &url, const QSize &requestSize);
 
+    static const QLatin1String itemGrabberScheme;
+
 private:
     Q_DISABLE_COPY(QQuickPixmap)
     QQuickPixmapData *d;
diff --git a/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml b/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml
index 022e98a202..a80814d6de 100644
--- a/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml
+++ b/tests/auto/qmltest/itemgrabber/tst_itemgrabber.qml
@@ -37,8 +37,9 @@ Item {
     TestCase {
         id: testCase
         name: "item-grabber"
-        when: imageOnDisk.ready && imageOnDiskSmall.ready && imageInCache.ready && imageInCacheSmall.ready
-        function test_endresult() {
+        when: imageOnDisk.ready && imageOnDiskSmall.ready
+
+        function test_endresult_disk() {
             var image = grabImage(root);
 
             // imageOnDisk at (0, 0) - (100x100)
@@ -52,6 +53,40 @@ Item {
             compare(imageOnDiskSmall.height, 50);
             verify(image.pixel(100, 0) === Qt.rgba(1, 0, 0, 1));
             verify(image.pixel(149, 49) === Qt.rgba(0, 0, 1, 1));
+        }
+
+        function test_endresult_cache_data() {
+            return [
+                { cache: true, sourceSize: Qt.size(-1, -1), fillMode: Image.Stretch },
+                { cache: true, sourceSize: Qt.size(-1, -1), fillMode: Image.PreserveAspectFit },
+                { cache: true, sourceSize: Qt.size(-1, -1), fillMode: Image.PreserveAspectCrop },
+                { cache: true, sourceSize: Qt.size(10, 10), fillMode: Image.Stretch },
+                { cache: true, sourceSize: Qt.size(10, 10), fillMode: Image.PreserveAspectFit },
+                { cache: true, sourceSize: Qt.size(10, 10), fillMode: Image.PreserveAspectCrop },
+                { cache: false, sourceSize: Qt.size(-1, -1), fillMode: Image.Stretch },
+                { cache: false, sourceSize: Qt.size(-1, -1), fillMode: Image.PreserveAspectFit },
+                { cache: false, sourceSize: Qt.size(-1, -1), fillMode: Image.PreserveAspectCrop },
+                { cache: false, sourceSize: Qt.size(10, 10), fillMode: Image.Stretch },
+                { cache: false, sourceSize: Qt.size(10, 10), fillMode: Image.PreserveAspectFit },
+                { cache: false, sourceSize: Qt.size(10, 10), fillMode: Image.PreserveAspectCrop },
+            ];
+        }
+
+        function test_endresult_cache(data) {
+            imageInCache.cache = data.cache;
+            imageInCache.sourceSize = data.sourceSize;
+            imageInCache.fillMode = data.fillMode;
+            imageInCacheSmall.cache = data.cache;
+            imageInCacheSmall.sourceSize = data.sourceSize;
+            imageInCacheSmall.fillMode = data.fillMode;
+
+            box.grabToImage(imageInCache.handleGrab);
+            box.grabToImage(imageInCacheSmall.handleGrab, Qt.size(50, 50));
+
+            tryCompare(imageInCache, "ready", true);
+            tryCompare(imageInCacheSmall, "ready", true);
+
+            var image = grabImage(root);
 
             // imageInCache at (0, 100) - 100x100
             compare(imageInCache.width, 100);
@@ -72,8 +107,6 @@ Item {
         onWindowShownChanged: {
             box.grabToImage(imageOnDisk.handleGrab);
             box.grabToImage(imageOnDiskSmall.handleGrab, Qt.size(50, 50));
-            box.grabToImage(imageInCache.handleGrab);
-            box.grabToImage(imageInCacheSmall.handleGrab, Qt.size(50, 50));
         }
 
     }