Cache the clipboard QImage, share with provider

src/clipboard.h

@@ -46,11 +46,20 @@ public:
         this->clipboard->setText(text, QClipboard::Clipboard);
     }
 
-    QByteArray image() const {
+    QImage *qimage() {
+        if (this->cachedImage.isNull())
+            this->cachedImage = this->clipboard->image();
+
+        return &(this->cachedImage);
+    }
+
+    QByteArray image() {
         QByteArray byteArray;
         QBuffer buffer(&byteArray);
         buffer.open(QIODevice::WriteOnly);
-        this->clipboard->image(QClipboard::Clipboard).save(&buffer, "PNG");
+        QImage *image = this->qimage();
+        // minimum compression, fastest to not freeze the UI
+        image->save(&buffer, "PNG", 100);
         buffer.close();
         return byteArray;
     }
@@ -90,9 +99,11 @@ signals:
 
 private:
     QClipboard *clipboard = QGuiApplication::clipboard();
+    QImage cachedImage = QImage();
 
     void mainClipboardChanged() {
-        contentChanged();
+        this->contentChanged();
+        this->cachedImage = QImage();
         this->hasImage() ? this->imageChanged() : this->textChanged();
         this->hasImageChanged();
     };

src/clipboard_image_provider.h

@@ -3,36 +3,39 @@
 #ifndef CLIPBOARD_IMAGE_PROVIDER_H
 #define CLIPBOARD_IMAGE_PROVIDER_H
 
-#include <QClipboard>
 #include <QImage>
 #include <QQuickImageProvider>
 
+#include "clipboard.h"
+
 
 class ClipboardImageProvider : public QQuickImageProvider {
-
 public:
-    explicit ClipboardImageProvider()
-        : QQuickImageProvider(QQuickImageProvider::Image) {}
+    explicit ClipboardImageProvider(Clipboard *clipboard)
+        : QQuickImageProvider(QQuickImageProvider::Image)
+    {
+        this->clipboard = clipboard;
+    }
 
     QImage requestImage(
         const QString &id, QSize *size, const QSize &requestSize
     ) {
         Q_UNUSED(id);
 
-        QImage image = this->clipboard->image();
+        QImage *image = this->clipboard->qimage();
 
-        if (size) *size = image.size();
+        if (size) *size = image->size();
 
         if (requestSize.width() > 0 && requestSize.height() > 0)
-            image = image.scaled(
+            return image->scaled(
                 requestSize.width(), requestSize.height(), Qt::KeepAspectRatio
             );
 
-       return image;
+       return *image;
     }
 
 private:
-    QClipboard *clipboard = QGuiApplication::clipboard();
+    Clipboard *clipboard;
 };
 
 #endif

src/main.cpp

@@ -126,10 +126,12 @@ int main(int argc, char *argv[]) {
     objectContext->setContextProperty("debugMode", false);
 #endif
 
+    Clipboard *clipboard = new Clipboard();
+
     // Register out custom image providers.
     // QML will be able to request an image from them by setting an
     // `Image`'s `source` to `image://<providerId>/<id>`
-    engine.addImageProvider("clipboard", new ClipboardImageProvider);
+    engine.addImageProvider("clipboard",new ClipboardImageProvider(clipboard));
 
     // Register our custom non-visual QObject singletons,
     // that will be importable anywhere in QML. Example:
@@ -138,10 +140,10 @@ int main(int argc, char *argv[]) {
     //     Component.onCompleted: print(Clipboard.text)
     qmlRegisterSingletonType<Clipboard>(
         "Clipboard", 0, 1, "Clipboard",
-        [](QQmlEngine *engine, QJSEngine *scriptEngine) -> QObject * {
+        [clipboard](QQmlEngine *engine, QJSEngine *scriptEngine) -> QObject * {
             Q_UNUSED(engine)
             Q_UNUSED(scriptEngine)
-            return new Clipboard();
+            return clipboard;
         }
     );