Create GuiUtils functions createColorIcon() and createOpacityIcon()

* createColorIcon creates a QIcon which visualizes the given colors
  using rectangles. A background icon can be provided, in that case
  only the lowest 25% of the icon will be filled by the rectangles.
* createOpacityIcon creates a QIcon that visualizes a given opacity
  using the current foreground color and a checkerboard background.

These functions are now used in place of colorIcon, colorPicerIcon,
opacityIcon in AnnotationActionHandler. The new functions have some
advantages: support most common icon sizes, and dark color schemes.

ui/annotationactionhandler.cpp

@@ -89,10 +89,7 @@ public:
     void populateQuickAnnotations();
     KSelectAction *colorPickerAction(AnnotationColor colorType);
 
-    const QIcon colorIcon(const QColor &color);
     const QIcon widthIcon(double width);
-    const QIcon colorPickerIcon(const QString &iconName, const QColor &color);
-    const QIcon opacityIcon(double opacity);
     const QIcon stampIcon(const QString &stampIconName);
 
     void selectTool(int toolID);
@@ -154,7 +151,7 @@ const QList<QPair<QString, QColor>> AnnotationActionHandlerPrivate::defaultColor
 
 const QList<double> AnnotationActionHandlerPrivate::widthStandardValues = {1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5};
 
-const QList<double> AnnotationActionHandlerPrivate::opacityStandardValues = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
+const QList<double> AnnotationActionHandlerPrivate::opacityStandardValues = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0};
 
 QAction *AnnotationActionHandlerPrivate::selectActionItem(KSelectAction *aList, QAction *aCustomCurrent, double value, const QList<double> &defaultValues, const QIcon &icon, const QString &label)
 {
@@ -241,8 +238,8 @@ void AnnotationActionHandlerPrivate::parseTool(int toolID)
 
     // if the opacity value is not a default one, insert a new action in the opacity list
     if (annElement.hasAttribute(QStringLiteral("opacity"))) {
-        double opacity = 100 * annElement.attribute(QStringLiteral("opacity")).toDouble();
-        aCustomOpacity = selectActionItem(aOpacity, aCustomOpacity, opacity, opacityStandardValues, opacityIcon(opacity), i18nc("@item:inlistbox", "%1\%", opacity));
+        double opacity = annElement.attribute(QStringLiteral("opacity")).toDouble();
+        aCustomOpacity = selectActionItem(aOpacity, aCustomOpacity, opacity, opacityStandardValues, GuiUtils::createOpacityIcon(opacity), i18nc("@item:inlistbox", "%1\%", opacity * 100));
     } else {
         aOpacity->setCurrentItem(opacityStandardValues.size() - 1); // 100 %
     }
@@ -269,11 +266,11 @@ void AnnotationActionHandlerPrivate::updateConfigActions(const QString &annotTyp
     const bool isStamp = annotType == QStringLiteral("stamp");
 
     if (isTypewriter) {
-        aColor->setIcon(colorPickerIcon(QStringLiteral("format-text-color"), currentColor));
+        aColor->setIcon(GuiUtils::createColorIcon({currentColor}, QIcon::fromTheme(QStringLiteral("format-text-color"))));
     } else {
-        aColor->setIcon(colorPickerIcon(QStringLiteral("format-stroke-color"), currentColor));
+        aColor->setIcon(GuiUtils::createColorIcon({currentColor}, QIcon::fromTheme(QStringLiteral("format-stroke-color"))));
     }
-    aInnerColor->setIcon(colorPickerIcon(QStringLiteral("format-fill-color"), currentInnerColor));
+    aInnerColor->setIcon(GuiUtils::createColorIcon({currentInnerColor}, QIcon::fromTheme(QStringLiteral("format-fill-color"))));
 
     aAddToQuickTools->setEnabled(isAnnotationSelected);
     aWidth->setEnabled(isLine || isShape);
@@ -393,7 +390,7 @@ KSelectAction *AnnotationActionHandlerPrivate::colorPickerAction(AnnotationColor
     aColorPicker->setToolBarMode(KSelectAction::MenuMode);
     for (const auto &colorNameValue : colorList) {
         QColor color(colorNameValue.second);
-        QAction *aColor = new QAction(colorIcon(color), i18nc("@item:inlistbox Color name", "%1", colorNameValue.first), q);
+        QAction *aColor = new QAction(GuiUtils::createColorIcon({color}, QIcon(), GuiUtils::VisualizeTransparent), i18nc("@item:inlistbox Color name", "%1", colorNameValue.first), q);
         aColorPicker->addAction(aColor);
         QObject::connect(aColor, &QAction::triggered, q, [this, colorType, color]() { slotSetColor(colorType, color); });
     }
@@ -415,53 +412,6 @@ const QIcon AnnotationActionHandlerPrivate::widthIcon(double width)
     return QIcon(pm);
 }
 
-const QIcon AnnotationActionHandlerPrivate::colorPickerIcon(const QString &iconName, const QColor &color)
-{
-    QIcon icon = QIcon::fromTheme(iconName);
-    if (!color.isValid()) {
-        return icon;
-    }
-    QSize iconSize = QSize(32, 32);
-    QPixmap pm = icon.pixmap(iconSize);
-    QPainter p(&pm);
-    p.fillRect(0, iconSize.height() - 8, iconSize.width(), 8, color);
-    p.end();
-    return QIcon(pm);
-}
-
-const QIcon AnnotationActionHandlerPrivate::colorIcon(const QColor &color)
-{
-    QSize iconSize = QSize(32, 32);
-    QPixmap pm(iconSize);
-    QPainter p(&pm);
-    if (color == Qt::transparent) {
-        p.fillRect(0, 0, iconSize.width(), iconSize.height(), Qt::white);
-        p.setPen(QPen(Qt::red, 2));
-        p.drawLine(iconSize.width() - 1, 0, 0, iconSize.height() - 1);
-    } else {
-        p.fillRect(0, 0, iconSize.width(), iconSize.height(), color);
-    }
-    p.setPen(Qt::black);
-    p.drawRect(0, 0, iconSize.width() - 1, iconSize.height() - 1);
-    p.end();
-    return QIcon(pm);
-}
-
-const QIcon AnnotationActionHandlerPrivate::opacityIcon(double opacity)
-{
-    QPixmap pm(32, 32);
-    pm.fill(Qt::transparent);
-    QPainter p(&pm);
-    p.setRenderHint(QPainter::Antialiasing);
-    p.setPen(Qt::NoPen);
-    QColor color(Qt::black);
-    color.setAlpha(opacity * 255 / 100);
-    p.setBrush(QBrush(color));
-    p.drawRect(4, 4, 24, 24);
-    p.end();
-    return QIcon(pm);
-}
-
 const QIcon AnnotationActionHandlerPrivate::stampIcon(const QString &stampIconName)
 {
     QPixmap stampPix = GuiUtils::loadStamp(stampIconName, 32);
@@ -683,10 +633,10 @@ AnnotationActionHandler::AnnotationActionHandler(PageViewAnnotator *parent, KAct
     // Opacity list
     d->aOpacity = new KSelectAction(QIcon::fromTheme(QStringLiteral("edit-opacity")), i18nc("@action:intoolbar Current annotation config option", "Opacity"), this);
     d->aOpacity->setToolBarMode(KSelectAction::MenuMode);
-    for (auto opacity : d->opacityStandardValues) {
-        KToggleAction *ann = new KToggleAction(d->opacityIcon(opacity), QStringLiteral("%1\%").arg(opacity), this);
+    for (double opacity : d->opacityStandardValues) {
+        KToggleAction *ann = new KToggleAction(GuiUtils::createOpacityIcon(opacity), QStringLiteral("%1\%").arg(opacity * 100), this);
         d->aOpacity->addAction(ann);
-        connect(ann, &QAction::triggered, this, [this, opacity]() { d->annotator->setAnnotationOpacity(opacity / 100); });
+        connect(ann, &QAction::triggered, this, [this, opacity]() { d->annotator->setAnnotationOpacity(opacity); });
     }
 
     connect(d->aAddToQuickTools, &QAction::triggered, d->annotator, &PageViewAnnotator::addToQuickAnnotations);

ui/guiutils.cpp

@@ -13,6 +13,7 @@
 #include <KIconLoader>
 #include <KLocalizedString>
 #include <KMessageBox>
+#include <QApplication>
 #include <QFileDialog>
 #include <QPainter>
 #include <QStandardPaths>
@@ -278,4 +279,93 @@ void colorizeImage(QImage &grayImage, const QColor &color, unsigned int destAlph
     }
 }
 
+QIcon createColorIcon(const QList<QColor> &colors, const QIcon &background, ColorIconFlags flags)
+{
+    QIcon colorIcon;
+
+    // Create a pixmap for each common icon size.
+    for (int size : {16, 22, 24, 32, 48}) {
+        QPixmap pixmap(QSize(size, size) * qApp->devicePixelRatio());
+        pixmap.setDevicePixelRatio(qApp->devicePixelRatio());
+        pixmap.fill(Qt::transparent);
+        QPainter painter(&pixmap);
+        // Configure hairlines for visualization of outline or transparency (visualizeTransparent):
+        painter.setPen(QPen(qApp->palette().color(QPalette::Active, QPalette::WindowText), 0));
+        painter.setBrush(Qt::NoBrush);
+
+        if (background.isNull()) {
+            // Full-size color rectangles.
+            // Draw rectangles left to right:
+            for (int i = 0; i < colors.count(); ++i) {
+                if (!colors.at(i).isValid()) {
+                    continue;
+                }
+                QRect rect(QPoint(size * i / colors.count(), 0), QPoint(size * (i + 1) / colors.count(), size));
+                if ((flags & VisualizeTransparent) && (colors.at(i) == Qt::transparent)) {
+                    painter.drawLine(rect.topLeft(), rect.bottomRight());
+                    painter.drawLine(rect.bottomLeft(), rect.topRight());
+                } else {
+                    painter.fillRect(rect, colors.at(i));
+                }
+            }
+
+            // Draw hairline outline:
+            // To get the hairline on the outermost pixels, we shrink the rectangle by a half pixel on each edge.
+            const qreal halfPixelWidth = 0.5 / pixmap.devicePixelRatio();
+            painter.drawRect(QRectF(QPointF(halfPixelWidth, halfPixelWidth), QPointF(qreal(size) - halfPixelWidth, qreal(size) - halfPixelWidth)));
+        } else {
+            // Lower 25% color rectangles.
+            // Draw background icon:
+            background.paint(&painter, QRect(QPoint(0, 0), QSize(size, size)));
+
+            // Draw rectangles left to right:
+            for (int i = 0; i < colors.count(); ++i) {
+                if (!colors.at(i).isValid()) {
+                    continue;
+                }
+                QRect rect(QPoint(size * i / colors.count(), size * 3 / 4), QPoint(size * (i + 1) / colors.count(), size));
+                if ((flags & VisualizeTransparent) && (colors.at(i) == Qt::transparent)) {
+                    painter.drawLine(rect.topLeft(), rect.bottomRight());
+                    painter.drawLine(rect.bottomLeft(), rect.topRight());
+                } else {
+                    painter.fillRect(rect, colors.at(i));
+                }
+            }
+        }
+
+        painter.end();
+        colorIcon.addPixmap(pixmap);
+    }
+
+    return colorIcon;
+}
+
+QIcon createOpacityIcon(qreal opacity)
+{
+    QIcon opacityIcon;
+
+    // Create a pixmap for each common icon size.
+    for (int size : {16, 22, 24, 32, 48}) {
+        QPixmap pixmap(QSize(size, size) * qApp->devicePixelRatio());
+        pixmap.setDevicePixelRatio(qApp->devicePixelRatio());
+        pixmap.fill(Qt::transparent);
+        QPainter painter(&pixmap);
+        painter.setPen(Qt::NoPen);
+        painter.setBrush(qApp->palette().color(QPalette::Active, QPalette::WindowText));
+
+        // Checkerboard pattern
+        painter.drawRect(QRectF(QPoint(0, 0), QPoint(size, size) / 2));
+        painter.drawRect(QRectF(QPoint(size, size) / 2, QPoint(size, size)));
+
+        // Opacity
+        painter.setOpacity(opacity);
+        painter.drawRect(QRect(QPoint(0, 0), QPoint(size, size)));
+
+        painter.end();
+        opacityIcon.addPixmap(pixmap);
+    }
+
+    return opacityIcon;
+}
+
 }

ui/guiutils.h

@@ -10,9 +10,10 @@
 #ifndef OKULAR_GUIUTILS_H
 #define OKULAR_GUIUTILS_H
 
+#include <QColor>
+#include <QIcon>
 #include <QString>
 
-class QColor;
 class QImage;
 class QPixmap;
 class QSize;
@@ -65,6 +66,37 @@ Okular::Movie *renditionMovieFromScreenAnnotation(const Okular::ScreenAnnotation
 
 // colorize a gray image to the given color
 void colorizeImage(QImage &image, const QColor &color, unsigned int alpha = 255);
+
+enum ColorIconFlags {
+    NoFlags = 0x0,
+    VisualizeTransparent = 0x1 ///< Visualizes Qt::transparent with a cross.
+};
+
+/**
+ * Paints color rectangles on the lower 25% of an icon.
+ *
+ * If no icon is given, the whole icon square is filled, and a 1px border is added.
+ *
+ * Examples:
+ *  * Different icons for different kinds of color selection, like fill and outline.
+ *  * Selection of a color scheme preset, where each scheme has a different icon and ~1..3 specific colors.
+ *
+ * @param colors Which color rectangles to paint, from left to right (even on RTL). Colors may be transparent. Invalid colors are skipped.
+ * @param background Which icon to use as background.
+ * @param flags Special wishes.
+ *
+ * @returns A newly created QIcon.
+ */
+QIcon createColorIcon(const QList<QColor> &colors, const QIcon &background = QIcon(), ColorIconFlags flags = NoFlags);
+
+/**
+ * Creates an opacity icon, using QPalette foreground color
+ * painted on top of a checkerboard pattern using @p opacity.
+ *
+ * @param opacity 0 = invisible, 1 = opaque.
+ */
+QIcon createOpacityIcon(qreal opacity);
+
 }
 
 #endif