[app] Improved rendering of book covers

Especially narrow ones.

app/qml/BooksCoverPage.qml

@@ -1,20 +1,21 @@
 /*
-  Copyright (C) 2015 Jolla Ltd.
+  Copyright (C) 2015-2021 Jolla Ltd.
-  Contact: Slava Monich <slava.monich@jolla.com>
+  Copyright (C) 2015-2021 Slava Monich <slava.monich@jolla.com>
 
-  You may use this file under the terms of BSD license as follows:
+  You may use this file under the terms of the BSD license as follows:
 
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
+
     * Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.
     * Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in the
       documentation and/or other materials provided with the distribution.
-    * Neither the name of the Jolla Ltd nor the
+    * Neither the names of the copyright holders nor the names of its
-      names of its contributors may be used to endorse or promote products
+      contributors may be used to endorse or promote products derived
-      derived from this software without specific prior written permission.
+      from this software without specific prior written permission.
 
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
@@ -60,7 +61,7 @@ CoverBackground {
             width: grid.cellWidth
             height: grid.cellHeight
             borderWidth: 0
-            stretch: true
+            mode: BookCover.Stretch
         }
     }
 
@@ -95,7 +96,7 @@ CoverBackground {
         synchronous: true
         book: root.book ? root.book : null
         defaultCover: "images/default-cover.jpg"
-        stretch: true
+        mode: BookCover.Fill
     }
 
     BooksTitleText {

app/qml/BooksShelfItem.qml

@@ -103,6 +103,7 @@ Item {
         borderRadius: _borderRadius
         borderWidth: book ? _borderWidth : 0
         borderColor: _borderColor
+        mode: BookCover.Bottom
         opacity: (copyingIn || copyingOut) ? 0.1 : 1
         Behavior on opacity { FadeAnimation { } }
 

app/src/BooksCoverWidget.cpp

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2015-2018 Jolla Ltd.
+ * Copyright (C) 2015-2021 Jolla Ltd.
- * Copyright (C) 2015-2018 Slava Monich <slava.monich@jolla.com>
+ * Copyright (C) 2015-2021 Slava Monich <slava.monich@jolla.com>
  *
  * You may use this file under the terms of the BSD license as follows:
  *
@@ -8,15 +8,15 @@
  * modification, are permitted provided that the following conditions
  * are met:
  *
- *   * Redistributions of source code must retain the above copyright
+ *   1. Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer.
+ *      notice, this list of conditions and the following disclaimer.
- *   * Redistributions in binary form must reproduce the above copyright
+ *   2. Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in
+ *      notice, this list of conditions and the following disclaimer
- *     the documentation and/or other materials provided with the
+ *      in the documentation and/or other materials provided with the
- *     distribution.
+ *      distribution.
- *   * Neither the name of Nemo Mobile nor the names of its contributors
+ *   3. Neither the names of the copyright holders nor the names of its
- *     may be used to endorse or promote products derived from this
+ *      contributors may be used to endorse or promote products derived
- *     software without specific prior written permission.
+ *      from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -50,19 +50,28 @@ public:
     ScaleTask(QThreadPool* aPool, QImage aImage, int aWidth, int aHeight,
         bool aStretch);
     static QImage scale(QImage aImage, int aWidth, int aHeight, bool aStretch);
+    static QColor leftBackground(const QImage& aImage);
+    static QColor rightBackground(const QImage& aImage);
+    static QColor topBackground(const QImage& aImage);
+    static QColor bottomBackground(const QImage& aImage);
+    static QColor pickColor(const QHash<QRgb,int>& aColorCounts);
     void performTask();
 
 public:
     QImage iImage;
     QImage iScaledImage;
+    QColor iBackground1; // Left or top
+    QColor iBackground2; // Right or bottom
     int iWidth;
     int iHeight;
     bool iStretch;
 };
 
 BooksCoverWidget::ScaleTask::ScaleTask(QThreadPool* aPool, QImage aImage,
-    int aWidth, int aHeight, bool aStretch) : HarbourTask(aPool),
+    int aWidth, int aHeight, bool aStretch) : HarbourTask(aPool), iImage(aImage),
-    iImage(aImage), iWidth(aWidth), iHeight(aHeight), iStretch(aStretch)
+    iBackground1(Qt::transparent), iBackground2(Qt::transparent),
+    iWidth(aWidth), iHeight(aHeight),
+    iStretch(aStretch)
 {
 }
 
@@ -79,10 +88,106 @@ QImage BooksCoverWidget::ScaleTask::scale(QImage aImage,
     }
 }
 
+// The idea is to pick the colors which occur more often
+// at the edges of the picture.
+QColor BooksCoverWidget::ScaleTask::leftBackground(const QImage& aImage)
+{
+    QHash<QRgb,int> counts;
+    if (aImage.width() > 0) {
+        const int h = aImage.height();
+        for (int y = 0; y < h; y++) {
+            const QRgb left(aImage.pixelColor(0, y).rgb());
+            counts.insert(left, counts.value(left) + 1);
+        }
+    }
+    const QColor color(pickColor(counts));
+    HDEBUG(color << "left" << counts.count());
+    return color;
+}
+
+QColor BooksCoverWidget::ScaleTask::rightBackground(const QImage& aImage)
+{
+    QHash<QRgb,int> counts;
+    const int w = aImage.width();
+    if (w > 0) {
+        const int h = aImage.height();
+        for (int y = 0; y < h; y++) {
+            const QRgb right(aImage.pixelColor(w - 1, y).rgb());
+            counts.insert(right, counts.value(right) + 1);
+        }
+    }
+    const QColor color(pickColor(counts));
+    HDEBUG(color << "right" << counts.count());
+    return color;
+}
+
+QColor BooksCoverWidget::ScaleTask::topBackground(const QImage& aImage)
+{
+    QHash<QRgb,int> counts;
+    if (aImage.height() > 0) {
+        const int w = aImage.width();
+        for (int x = 0; x < w; x++) {
+            const QRgb left(aImage.pixelColor(x, 0).rgb());
+            counts.insert(left, counts.value(left) + 1);
+        }
+    }
+    const QColor color(pickColor(counts));
+    HDEBUG(color << "top" << counts.count());
+    return color;
+}
+
+QColor BooksCoverWidget::ScaleTask::bottomBackground(const QImage& aImage)
+{
+    QHash<QRgb,int> counts;
+    const int h = aImage.height();
+    if (h > 0) {
+        const int w = aImage.width();
+        for (int x = 0; x < w; x++) {
+            const QRgb left(aImage.pixelColor(x, h - 1).rgb());
+            counts.insert(left, counts.value(left) + 1);
+        }
+    }
+    const QColor color(pickColor(counts));
+    HDEBUG(color << "bottom" << counts.count());
+    return color;
+}
+
+QColor BooksCoverWidget::ScaleTask::pickColor(const QHash<QRgb,int>& aCounts)
+{
+    if (aCounts.size() > 0) {
+        QRgb rgb;
+        int max;
+        QHashIterator<QRgb,int> it(aCounts);
+        for (max = 0; it.hasNext();) {
+            it.next();
+            const int count = it.value();
+            if (max < count) {
+                max = count;
+                rgb = it.key();
+            }
+        }
+        return QColor(rgb);
+    }
+    return QColor();
+}
+
 void BooksCoverWidget::ScaleTask::performTask()
 {
     if (!iImage.isNull() && !isCanceled()) {
         iScaledImage = scale(iImage, iWidth, iHeight, iStretch);
+        if (!isCanceled()) {
+            if (iScaledImage.width() < iWidth) {
+                iBackground1 = leftBackground(iScaledImage);
+                if (!isCanceled()) {
+                    iBackground2 = rightBackground(iScaledImage);
+                }
+            } else if (iScaledImage.height() < iHeight) {
+                iBackground1 = topBackground(iScaledImage);
+                if (!isCanceled()) {
+                    iBackground2 = bottomBackground(iScaledImage);
+                }
+            }
+        }
     }
 }
 
@@ -204,7 +309,7 @@ BooksCoverWidget::BooksCoverWidget(QQuickItem* aParent) :
     iBorderWidth(0),
     iBorderRadius(0),
     iBorderColor(Qt::transparent),
-    iStretch(false),
+    iMode(Bottom),
     iSynchronous(false)
 {
     setFlag(ItemHasContents, true);
@@ -264,13 +369,13 @@ void BooksCoverWidget::onCoverImageChanged()
     scaleImage(wasEmpty);
 }
 
-void BooksCoverWidget::setStretch(bool aValue)
+void BooksCoverWidget::setMode(Mode aMode)
 {
-    if (iStretch != aValue) {
+    if (iMode != aMode) {
-        iStretch = aValue;
+        iMode = aMode;
-        HDEBUG(aValue);
+        HDEBUG(aMode);
         scaleImage();
-        Q_EMIT stretchChanged();
+        Q_EMIT modeChanged();
     }
 }
 
@@ -362,12 +467,20 @@ void BooksCoverWidget::scaleImage(bool aWasEmpty)
         }
 
         if (!iCoverImage.isNull()) {
+            const bool stretch = (iMode == Stretch);
             if (iSynchronous) {
-                iScaledImage = ScaleTask::scale(iCoverImage, w, h, iStretch);
+                iScaledImage = ScaleTask::scale(iCoverImage, w, h, stretch);
+                if (iScaledImage.width() < w) {
+                    iBackground1 = ScaleTask::leftBackground(iScaledImage);
+                    iBackground2 = ScaleTask::rightBackground(iScaledImage);
+                } else if (iScaledImage.height() < h) {
+                    iBackground1 = ScaleTask::topBackground(iScaledImage);
+                    iBackground2 = ScaleTask::bottomBackground(iScaledImage);
+                }
                 update();
             } else {
-                (iScaleTask = new ScaleTask(iTaskQueue->pool(), iCoverImage, w, h,
+                (iScaleTask = new ScaleTask(iTaskQueue->pool(), iCoverImage,
-                    iStretch))->submit(this, SLOT(onScaleTaskDone()));
+                    w, h, stretch))->submit(this, SLOT(onScaleTaskDone()));
             }
         } else {
             iScaledImage = QImage();
@@ -389,6 +502,8 @@ void BooksCoverWidget::onScaleTaskDone()
     const bool wasEmpty(empty());
     HASSERT(iScaleTask == sender());
     iScaledImage = iScaleTask->iScaledImage;
+    iBackground1 = iScaleTask->iBackground1;
+    iBackground2 = iScaleTask->iBackground2;
     iScaleTask->release(this);
     iScaleTask = NULL;
     update();
@@ -403,28 +518,17 @@ void BooksCoverWidget::paint(QPainter* aPainter)
     const qreal w = width();
     const qreal h = height();
     if (w > 0 && h > 0) {
-        qreal sw, sh;
-
         // This has to be consistent with updateCenter()
-        if (!iScaledImage.isNull()) {
+        const qreal sh = (iScaledImage.height() && iMode == Bottom) ?
-            sw = iScaledImage.width();
+            qMax((qreal)iScaledImage.height(), w) : h;
-            sh = iScaledImage.height();
-        } else {
-            sw = w;
-            sh = h;
-        }
-
-        const int x = floor((w - sw)/2);
-        const int y = h - sh;
 
         QPainterPath path;
         qreal w1, h1, x1, y1;
-
         if (iBorderRadius > 0) {
             // The border rectangle is no less that 3*radius
             // and no more than the size of the item.
             const qreal d = 2*iBorderRadius;
-            w1 = qMin(w, qMax(sw, 2*d)) - iBorderWidth;
+            w1 = qMin(w, qMax(w, 2*d)) - iBorderWidth;
             h1 = qMin(h, qMax(sh, 3*d)) - iBorderWidth;
             x1 = floor((w - w1)/2);
             y1 = h - h1 - iBorderWidth/2;
@@ -439,13 +543,41 @@ void BooksCoverWidget::paint(QPainter* aPainter)
             path.closeSubpath();
             aPainter->setClipPath(path);
         } else {
-            w1 = sw - iBorderWidth;
+            w1 = w - iBorderWidth;
             h1 = sh - iBorderWidth;
             x1 = floor((w - w1)/2);
             y1 = h - h1 - iBorderWidth/2;
         }
 
+        const int x = floor((w - iScaledImage.width())/2);
+        const int y = floor(h - (sh + iScaledImage.height())/2);
+
         if (!iScaledImage.isNull()) {
+            if (x > 0) {
+                aPainter->setPen(Qt::NoPen);
+                if (iBackground1.isValid()) {
+                    aPainter->setBrush(QBrush(iBackground1));
+                    aPainter->drawRect(0, y, x, iScaledImage.height());
+                }
+                if (iBackground2.isValid()) {
+                    const int left = x + iScaledImage.width();
+                    aPainter->setBrush(QBrush(iBackground2));
+                    aPainter->drawRect(left, y, x, iScaledImage.height());
+                }
+            } else {
+                const int top = h - sh;
+                if (y > top) {
+                    aPainter->setPen(Qt::NoPen);
+                    if (iBackground1.isValid()) {
+                        aPainter->setBrush(QBrush(iBackground1));
+                        aPainter->drawRect(0, 0, w, y - top);
+                    }
+                    if (iBackground2.isValid()) {
+                        aPainter->setBrush(QBrush(iBackground2));
+                        aPainter->drawRect(0, y + iScaledImage.height(), w, y - top);
+                    }
+                }
+            }
             aPainter->drawImage(x, y, iScaledImage);
         }
 
@@ -475,7 +607,8 @@ void BooksCoverWidget::updateCenter()
     if (iScaledImage.isNull()) {
         iCenter.setY(floor(h/2));
     } else {
-        iCenter.setY(floor(h - iScaledImage.height()/2));
+        const qreal sh = qMax((qreal)iScaledImage.height(), w);
+        iCenter.setY(floor(h - sh/2));
     }
 
     if (iCenter != oldCenter) {

app/src/BooksCoverWidget.h

@@ -1,6 +1,6 @@
 /*
- * Copyright (C) 2015-2018 Jolla Ltd.
+ * Copyright (C) 2015-2021 Jolla Ltd.
- * Copyright (C) 2015-2018 Slava Monich <slava.monich@jolla.com>
+ * Copyright (C) 2015-2021 Slava Monich <slava.monich@jolla.com>
  *
  * You may use this file under the terms of the BSD license as follows:
  *
@@ -8,15 +8,15 @@
  * modification, are permitted provided that the following conditions
  * are met:
  *
- *   * Redistributions of source code must retain the above copyright
+ *   1. Redistributions of source code must retain the above copyright
- *     notice, this list of conditions and the following disclaimer.
+ *      notice, this list of conditions and the following disclaimer.
- *   * Redistributions in binary form must reproduce the above copyright
+ *   2. Redistributions in binary form must reproduce the above copyright
- *     notice, this list of conditions and the following disclaimer in
+ *      notice, this list of conditions and the following disclaimer
- *     the documentation and/or other materials provided with the
+ *      in the documentation and/or other materials provided with the
- *     distribution.
+ *      distribution.
- *   * Neither the name of Nemo Mobile nor the names of its contributors
+ *   3. Neither the names of the copyright holders nor the names of its
- *     may be used to endorse or promote products derived from this
+ *      contributors may be used to endorse or promote products derived
- *     software without specific prior written permission.
+ *      from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
@@ -49,8 +49,8 @@ class BooksCoverWidget: public QQuickPaintedItem
     Q_OBJECT
     Q_PROPERTY(bool empty READ empty NOTIFY emptyChanged)
     Q_PROPERTY(bool loading READ loading NOTIFY loadingChanged)
-    Q_PROPERTY(bool stretch READ stretch WRITE setStretch NOTIFY stretchChanged)
     Q_PROPERTY(bool synchronous READ synchronous WRITE setSynchronous NOTIFY synchronousChanged)
+    Q_PROPERTY(Mode mode READ mode WRITE setMode NOTIFY modeChanged)
     Q_PROPERTY(qreal borderWidth READ borderWidth WRITE setBorderWidth NOTIFY borderWidthChanged)
     Q_PROPERTY(qreal borderRadius READ borderRadius WRITE setBorderRadius NOTIFY borderRadiusChanged)
     Q_PROPERTY(QColor borderColor READ borderColor WRITE setBorderColor NOTIFY borderColorChanged)
@@ -59,8 +59,15 @@ class BooksCoverWidget: public QQuickPaintedItem
     Q_PROPERTY(qreal centerX READ centerX NOTIFY centerXChanged)
     Q_PROPERTY(qreal centerY READ centerY NOTIFY centerYChanged)
     Q_PROPERTY(QPoint center READ center NOTIFY centerChanged)
+    Q_ENUMS(Mode)
 
 public:
+    enum Mode {
+        Fill,
+        Stretch,
+        Bottom
+    };
+
     BooksCoverWidget(QQuickItem* aParent = NULL);
     ~BooksCoverWidget();
 
@@ -82,8 +89,8 @@ public:
     BooksBook* book() const { return iBook; }
     void setBook(BooksBook* aBook);
 
-    bool stretch() const { return iStretch; }
+    Mode mode() const { return iMode; }
-    void setStretch(bool aValue);
+    void setMode(Mode aMode);
 
     bool synchronous() const { return iSynchronous; }
     void setSynchronous(bool aValue);
@@ -96,8 +103,8 @@ Q_SIGNALS:
     void bookChanged();
     void emptyChanged();
     void loadingChanged();
-    void stretchChanged();
     void synchronousChanged();
+    void modeChanged();
     void borderWidthChanged();
     void borderRadiusChanged();
     void borderColorChanged();
@@ -124,6 +131,8 @@ private:
     ScaleTask* iScaleTask;
     QImage iScaledImage;
     QImage iCoverImage;
+    QColor iBackground1;
+    QColor iBackground2;
     BooksBook* iBook;
     QImage* iDefaultImage;
     qreal iBorderWidth;
@@ -132,7 +141,7 @@ private:
     QUrl iDefaultCover;
     QString iTitle;
     QPoint iCenter;
-    bool iStretch;
+    Mode iMode;
     bool iSynchronous;
 };