From a65f9df18ff16eb9fe43417e5dfd602fff9af26c Mon Sep 17 00:00:00 2001
From: "craig.p.drummond" <craig.p.drummond@gmail.com>
Date: Fri, 22 Mar 2013 20:55:47 +0000
Subject: [PATCH] Fade edges of image

---
 widgets/textbrowser.cpp | 85 +++++++++++++++++++++++++++++++++++++++--
 widgets/textbrowser.h   |  2 +-
 2 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/widgets/textbrowser.cpp b/widgets/textbrowser.cpp
index ab903d58d..60a573e28 100644
--- a/widgets/textbrowser.cpp
+++ b/widgets/textbrowser.cpp
@@ -23,15 +23,90 @@
 
 #include "textbrowser.h"
 #include <QPainter>
+#include <QDebug>
 
-static const int constMinSize=300;
+static int border=-1;
+static int minSize=-1;
+static int maxSize=-1;
+
+static void fadeEdges(QImage &img, int edgeSize)
+{
+    unsigned char *data=img.bits();
+    int width=img.width()*4;
+    int height=img.height();
+
+    for (int i=0; i<edgeSize; ++i) {
+        int alpha=((i+1.0)/(edgeSize*1.0))*255;
+        int offset=i*img.bytesPerLine();
+        for(int column=i*4; column<width; column+=4) {
+            #if Q_BYTE_ORDER == Q_BIG_ENDIAN
+            // ARGB
+            data[offset+column] = alpha;
+            #else
+            // BGRA
+            data[offset+column+3] = alpha;
+            #endif
+        }
+        offset=img.bytesPerLine()*(height-1);
+        for(int column=i*4; column<width; column+=4) {
+            #if Q_BYTE_ORDER == Q_BIG_ENDIAN
+            // ARGB
+            data[offset+column] = alpha;
+            #else
+            // BGRA
+            data[offset+column+3] = alpha;
+            #endif
+        }
+        for (int j=i; j<height; ++j) {
+            offset=(img.bytesPerLine()*j)+(i*4);
+            #if Q_BYTE_ORDER == Q_BIG_ENDIAN
+            // ARGB
+            data[offset] = alpha;
+            #else
+            // BGRA
+            data[offset+3] = alpha;
+            #endif
+
+            offset=img.bytesPerLine()*j;
+            #if Q_BYTE_ORDER == Q_BIG_ENDIAN
+            // ARGB
+            data[offset+(width-4)] = alpha;
+            #else
+            // BGRA
+            data[offset+3+(width-4)] = alpha;
+            #endif
+        }
+        width-=4;
+        height--;
+    }
+}
+
+TextBrowser::TextBrowser(QWidget *p)
+    : QTextBrowser(p)
+    , drawImage(false)
+{
+    orig=font().pointSize();
+    if (-1==minSize) {
+        minSize=fontMetrics().height()*18;
+        minSize=(((int)(minSize/100))*100)+(minSize%100 ? 100 : 0);
+        maxSize=minSize*2;
+        border=minSize/4;
+    }
+}
 
 void TextBrowser::setImage(const QImage &img)
 {
     if (drawImage && (!img.isNull() || (img.isNull()!=image.isNull()))) {
         image=img;
-        if (!image.isNull() && (image.width()<constMinSize || image.height()<constMinSize)) {
-            image=image.scaled(QSize(constMinSize, constMinSize), Qt::KeepAspectRatio, Qt::SmoothTransformation);
+        if (!image.isNull()) {
+            if (image.width()<minSize || image.height()<minSize) {
+                image=image.scaled(QSize(maxSize, maxSize), Qt::KeepAspectRatio, Qt::SmoothTransformation);
+            } else if (image.width()>maxSize || image.height()>maxSize) {
+                image=image.scaled(QSize(maxSize, maxSize), Qt::KeepAspectRatio, Qt::SmoothTransformation);
+            }
+
+            image=image.convertToFormat(QImage::Format_ARGB32);
+            fadeEdges(image, border);
         }
         viewport()->update();
     }
@@ -56,6 +131,10 @@ void TextBrowser::paintEvent(QPaintEvent *e)
     if (drawImage && isReadOnly() && !image.isNull()) {
         QPainter p(viewport());
         p.setOpacity(0.15);
+//        QRect r(rect());
+//        int xpos=r.x()+(r.width()>image.width() ? ((r.width()-image.width())/2) : 0);
+//        int ypos=r.y()+(r.height()>image.height() ? ((r.height()-image.height())/2) : 0);
+//        p.drawImage(xpos, ypos, image);
         p.fillRect(rect(), QBrush(image));
     } else if (!viewport()->autoFillBackground()) {
         QPainter p(viewport());
diff --git a/widgets/textbrowser.h b/widgets/textbrowser.h
index 0daec18e4..028d59325 100644
--- a/widgets/textbrowser.h
+++ b/widgets/textbrowser.h
@@ -31,7 +31,7 @@
 class TextBrowser : public QTextBrowser
 {
 public:
-    TextBrowser(QWidget *p) : QTextBrowser(p) , drawImage(false) { orig=font().pointSize(); }
+    TextBrowser(QWidget *p);
     virtual ~TextBrowser() {  }
 
     void setZoom(int diff) { if (diff) zoomIn(diff);  }