proof of concept for composited effects by toying with the backing store

svn path=/trunk/KDE/kdebase/workspace/lib/plasma/; revision=672646

effects/blur.cpp

@@ -0,0 +1,130 @@
+
+#include <cmath>
+
+// Exponential blur, Jani Huhtanen, 2006
+//
+template<int aprec, int zprec>
+static inline void blurinner(unsigned char *bptr, int &zR, int &zG, int &zB, int &zA, int alpha);
+
+template<int aprec,int zprec>
+static inline void blurrow( QImage & im, int line, int alpha);
+
+template<int aprec, int zprec>
+static inline void blurcol( QImage & im, int col, int alpha);
+
+/*
+*  expblur(QImage &img, int radius)
+*
+*  In-place blur of image 'img' with kernel
+*  of approximate radius 'radius'.
+*
+*  Blurs with two sided exponential impulse
+*  response.
+*
+*  aprec = precision of alpha parameter 
+*  in fixed-point format 0.aprec
+*
+*  zprec = precision of state parameters
+*  zR,zG,zB and zA in fp format 8.zprec
+*/
+template<int aprec,int zprec>
+void expblur( QImage &img, int radius )
+{
+  if(radius<1)
+    return;
+
+  /* Calculate the alpha such that 90% of 
+     the kernel is within the radius.
+     (Kernel extends to infinity) 
+  */
+  int alpha = (int)((1<<aprec)*(1.0f-expf(-2.3f/(radius+1.f))));
+
+  for(int row=0;row<img.height();row++)
+  {
+    blurrow<aprec,zprec>(img,row,alpha);
+  }
+
+  for(int col=0;col<img.width();col++)
+  {
+    blurcol<aprec,zprec>(img,col,alpha);
+  }
+  return;
+}
+
+template<int aprec, int zprec>
+static inline void blurinner(unsigned char *bptr, int &zR, int &zG, int &zB, int &zA, int alpha)
+{
+  int R,G,B,A;
+  R = *bptr;
+  G = *(bptr+1);
+  B = *(bptr+2);
+  A = *(bptr+3);
+
+  zR += (alpha * ((R<<zprec)-zR))>>aprec;
+  zG += (alpha * ((G<<zprec)-zG))>>aprec;
+  zB += (alpha * ((B<<zprec)-zB))>>aprec;
+  zA += (alpha * ((A<<zprec)-zA))>>aprec;
+
+  *bptr =     zR>>zprec;
+  *(bptr+1) = zG>>zprec;
+  *(bptr+2) = zB>>zprec;
+  *(bptr+3) = zA>>zprec;
+}
+
+template<int aprec,int zprec>
+static inline void blurrow( QImage & im, int line, int alpha)
+{
+  int zR,zG,zB,zA;
+
+  QRgb *ptr = (QRgb *)im.scanLine(line);
+
+  zR = *((unsigned char *)ptr    )<<zprec;
+  zG = *((unsigned char *)ptr + 1)<<zprec;
+  zB = *((unsigned char *)ptr + 2)<<zprec;
+  zA = *((unsigned char *)ptr + 3)<<zprec;
+
+  for(int index=1; index<im.width(); index++)
+  {
+    blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
+  }
+  for(int index=im.width()-2; index>=0; index--)
+  {
+    blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
+  }
+ 
+
+}
+
+template<int aprec, int zprec>
+static inline void blurcol( QImage & im, int col, int alpha)
+{
+  int zR,zG,zB,zA;
+
+  QRgb *ptr = (QRgb *)im.bits();
+  ptr+=col;
+
+  zR = *((unsigned char *)ptr    )<<zprec;
+  zG = *((unsigned char *)ptr + 1)<<zprec;
+  zB = *((unsigned char *)ptr + 2)<<zprec;
+  zA = *((unsigned char *)ptr + 3)<<zprec;
+
+  for(int index=im.width(); index<(im.height()-1)*im.width(); index+=im.width())
+  {
+    blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
+  }
+
+  for(int index=(im.height()-2)*im.width(); index>=0; index-=im.width())
+  {
+    blurinner<aprec,zprec>((unsigned char *)&ptr[index],zR,zG,zB,zA,alpha);
+  }
+
+}
+
+template<class T>
+inline const T& qClamp(const T &x, const T &low, const T &high)
+{
+    if      (x <  low) return low;
+    else if (x > high) return high;
+    else               return x;
+}
+

widgets/icon.cpp

@@ -20,11 +20,15 @@
 
 #include <QPainter>
 #include <QGraphicsSceneMouseEvent>
+#include <QGraphicsView>
+#include <private/qwindowsurface_p.h>
 
 #include <KIcon>
+#include <KImageEffect>
 #include <KDebug>
 
 #include "svg.h"
+#include "blur.cpp"
 
 namespace Plasma
 {
@@ -121,6 +125,22 @@ void Icon::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWid
 
 //    QRectF rect = boundingRect();
 
+    if (d->state != Private::PressedState && scene()) {
+        QList<QGraphicsView*> views = scene()->views();
+        if (views.count() > 0) {
+            QPixmap* pix = static_cast<QPixmap*>(views[0]->windowSurface()->paintDevice());
+            QImage image(boundingRect().size().toSize(), QImage::Format_ARGB32_Premultiplied);
+            {
+                QPainter p(&image);
+                p.drawPixmap(image.rect(), *pix, sceneBoundingRect());
+            }
+            expblur<16,7>(image, 10);
+            painter->save();
+            painter->drawImage(0, 0, image);
+            painter->restore();
+        }
+    }
+
     QString element;
     if (d->svgElements & Private::SvgBackground) {
         element = "background";