Fixed many drawing issues (many ones being related to the flipping).

See bug report #27782

In particular, fixed -[NSImage drawXXX] and -[NSImage composite/dissolveXXX] 
methods to work exactly as Cocoa when the Cairo backend is used.
Added a new draw operator (in addition to composite) to the backend. Cairo is 
the only backend that implements it for now.
Eliminated as many flipping checks as possible.

Warning: Untested with the winlib backend. 
You must update, recompile and install both Back and Gui.


git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@30523 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,44 @@
+2010-06-01  Quentin Mathe <quentin.mathe@gmail.com>
+
+	Fixed many drawing issues (many ones being related to the flipping).
+	In particular, fixed -[NSImage drawXXX] methods to work exactly as 
+	Cocoa and improve the drawing performance in some cases (the last two 
+	points only holds with Cairo backend).
+	Eliminated as many flipping checks as possible.
+	Warning: Untested with the winlib backend.
+	* Headers/AppKit/NSGraphicsContext.h:
+	* Source/NSGraphicsContext.m:
+	(-supportsDrawGState, -GSdraw:toPoint:fromRect:operation:fraction:): 
+	Added (see also the Backend Changelog).
+	* Source/NSImage.m
+	(-drawInRect:fromRect:operation:fraction:): Moved the previous 
+	implementation to -guiDrawInRect:fromRect:operation:fraction: and 
+	rewritten as a switch that checks -supportsDrawState.
+	(-guiDrawInRect:fromRect:operation:fraction:): New method identical to 
+	the old -drawInRect:fromRect:operation:fraction:.
+	(-nativeDrawInRect:fromRect:operation:fraction:): Added. 
+	New method that leverages the backend as much possible and implement 
+	semantic that exactly matches Cocoa.
+	(-drawRepresentation:inRect:): Removed flipping 
+	check.
+	* Source/NSImageRep.m (-drawInPoint:, -drawInRect:): Removed the 
+	flipping checks.
+	* Source/NSImageCell.m (-drawInteriorWithFrame:inView:): Fixed 
+	-drawInRect:fromRect:operation:fraction use as Apple doc suggests it 
+	rather than using a negative height trick which doesn't work anymore 
+	(at least with Cairo) and has never worked on Mac OS X.
+	* Source/NSView.m (-scrollRect:by:): Ajusted to do the copy bits on 
+	the window gstate rather than the view gstate. 
+	Required now that Cairo NSCopyBits/compositeGState won't compensate the 
+	flipping when copyOnSelf is YES. Moreover -scrollRect:by: was broken 
+	previously when the view wass not flipped (at least for Cairo). 
+	Finally NSCopyBits() behaves in another way on Mac OS X when the view 
+	gstate is used instead of the window gstate. By using the window gstate, 
+	we can more easily change how NSCopyBits() handles the view gstate to 
+	match Cocoa.
+	* Source/NSClipView.m (-setBoundsOrigin:): Turned off dubious code that 
+	should probably be removed. 
+
 2010-06-01  Wolfgang Lux  <wolfgang.lux@gmail.com>
 
 	* Source/NSDocumentController.m (-_setupOpenPanel): Disable

Headers/AppKit/NSGraphicsContext.h

@@ -410,6 +410,12 @@ APPKIT_EXPORT NSGraphicsContext	*GSCurrentContext(void);
 	    fromRect: (NSRect)srcRect
 	   operation: (NSCompositingOperation)op
 	    fraction: (float)delta;
+- (BOOL) supportsDrawGState;
+- (void) GSdraw: (int)gstateNum
+        toPoint: (NSPoint)aPoint
+       fromRect: (NSRect)srcRect
+      operation: (NSCompositingOperation)op
+       fraction: (float)delta;
 - (void) GSDrawImage: (NSRect)rect : (void *)imageref;
 
 /* ----------------------------------------------------------------------- */

Headers/AppKit/NSView.h

@@ -118,6 +118,7 @@ PACKAGE_SCOPE
   int _gstate;
   void *_nextKeyView;
   void *_previousKeyView;
+  NSRect *_dirtyRects;
 
 @public
   /*

Source/NSClipView.m

@@ -372,11 +372,11 @@ static inline NSRect integralRect (NSRect rect, NSView *view)
     }
 
   /* ?? TODO: Understand the following code - and add explanatory comment */
-  if ([NSView focusView] == _documentView)
+  /*if ([NSView focusView] == _documentView)
     {
       PStranslate (NSMinX (originalBounds) - aPoint.x, 
 		   NSMinY (originalBounds) - aPoint.y);
-    }
+    }*/
   
   [_super_view reflectScrolledClipView: self];
 }

Source/NSGraphicsContext.m

@@ -1540,6 +1540,44 @@ NSGraphicsContext	*GSCurrentContext(void)
   [self subclassResponsibility: _cmd];
 }
 
+/** <override-dummy />
+Returns whether the backend supports a GSDraw operator.
+
+By default, returns NO.<br />
+When a GSContext backend subclass overrides this method to return YES, the 
+backend must also implement -drawGState:fromRect:toPoint:op:fraction: in its 
+GSState subclass.
+
+When YES is returned, -[NSImage drawXXX] methods that involves rotation, 
+scaling etc. will delegate as much as possible the image drawing to the backend, 
+rather than trying to emulate the resulting image in Gui by using intermediate 
+images to rotate and scale the content, and then composite the result with 
+-GScomposite:toPoint:fromRect:operation:fraction:.
+
+Backends which doesn't implement -compositeGState:fromRect:toPoint:op:fraction: 
+can draw rotated or scaled images, but the semantic won't exactly match the 
+NSImage documentation in non-trivial cases. */
+- (BOOL) supportsDrawGState
+{
+  return NO;
+}
+
+/** <override-dummy />
+Draws a gstate in a way that fully respects the destination transform, 
+unlike the GSComposite operator which ignores the rotation and the scaling 
+effect on the content.
+
+Note: For the GScomposite operator, the scaling and rotation affects the 
+destination point but not the content. */
+- (void) GSdraw: (int)gstateNum
+        toPoint: (NSPoint)aPoint
+       fromRect: (NSRect)srcRect
+      operation: (NSCompositingOperation)op
+       fraction: (float)delta
+{
+  [self subclassResponsibility: _cmd];
+}
+
 /** Generic method to draw an image into a rect. The image is defined
     by imageref, an opaque structure. Support for this method hasn't
     been implemented yet, so it should not be used anywhere. */

Source/NSImage.m

@@ -797,7 +797,6 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
   return _color;
 }
 
-
 // Using the Image 
 - (void) compositeToPoint: (NSPoint)aPoint 
                 operation: (NSCompositingOperation)op
@@ -813,8 +812,8 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
                  fromRect: (NSRect)aRect
                 operation: (NSCompositingOperation)op
 {
-  [self compositeToPoint: aPoint
-        fromRect: aRect
+  [self compositeToPoint: aPoint 
+        fromRect: aRect 
         operation: op
         fraction: 1.0];
 }
@@ -850,27 +849,27 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
 
       if (cache != nil)
         {
+          NSGraphicsContext *ctxt = GSCurrentContext();
           NSRect rect = [cache rect];
 
           NSDebugLLog(@"NSImage", @"composite rect %@ in %@", 
                       NSStringFromRect(rect), NSStringFromRect(srcRect));
+
           // Move the drawing rectangle to the origin of the image rep
           // and intersect the two rects.
           srcRect.origin.x += rect.origin.x;
           srcRect.origin.y += rect.origin.y;
           rect = NSIntersectionRect(srcRect, rect);
           
-          [GSCurrentContext() GScomposite: [[cache window] gState]
-                           toPoint: aPoint
-                           fromRect: rect
-                           operation: op
-                           fraction: delta];
+          [ctxt GScomposite: [[cache window] gState]
+                    toPoint: aPoint
+                   fromRect: rect
+                  operation: op
+                   fraction: delta];
         }
       else        
         {
-          NSRect rect;
-
-          rect = NSMakeRect(aPoint.x, aPoint.y, _size.width, _size.height);
+          NSRect rect = NSMakeRect(aPoint.x, aPoint.y, _size.width, _size.height);
           [self drawRepresentation: rep inRect: rect];
         }
     }
@@ -922,9 +921,6 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
     {
       NSRect fillrect = aRect;
 
-      if ([[NSView focusView] isFlipped])
-        fillrect.origin.y -= _size.height;
-
       [_color set];
       NSRectFill(fillrect);
 
@@ -957,10 +953,145 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
         fraction: delta];
 }
 
-- (void) drawInRect: (NSRect)dstRect
-           fromRect: (NSRect)srcRect
-          operation: (NSCompositingOperation)op
-           fraction: (float)delta
+/* New code path that delegates as much as possible to the backend and whose 
+behavior precisely matches Cocoa. */
+- (void) nativeDrawInRect: (NSRect)dstRect
+                 fromRect: (NSRect)srcRect
+                operation: (NSCompositingOperation)op
+                 fraction: (float)delta
+{
+  NSGraphicsContext *ctxt = GSCurrentContext();
+  NSSize imgSize = [self size];
+  float widthScaleFactor;
+  float heightScaleFactor;
+
+  if (NSEqualRects(srcRect, NSZeroRect))
+    {
+      srcRect.size = imgSize;
+      /* For -drawAtPoint:fromRect:operation:fraction: used with a zero rect */
+      if (NSEqualSizes(dstRect.size, NSZeroSize))
+        {
+          dstRect.size = imgSize;
+        }
+    }
+
+  if (!dstRect.size.width || !dstRect.size.height
+    || !srcRect.size.width || !srcRect.size.height)
+    return;
+
+  // Clip to image bounds
+  if (srcRect.origin.x < 0)
+    srcRect.origin.x = 0;
+  if (srcRect.origin.y < 0)
+    srcRect.origin.y = 0;
+  if (NSMaxX(srcRect) > imgSize.width)
+    srcRect.size.width = imgSize.width - srcRect.origin.x;
+  if (NSMaxY(srcRect) > imgSize.height)
+    srcRect.size.height = imgSize.height - srcRect.origin.y;
+
+  widthScaleFactor = dstRect.size.width / srcRect.size.width;
+  heightScaleFactor = dstRect.size.height / srcRect.size.height;
+
+  if (![ctxt isDrawingToScreen])
+    {
+      /* We can't composite or dissolve if we aren't drawing to a screen,
+         so we'll just draw the right part of the image in the right
+         place. */
+      NSPoint p;
+  
+      p.x = dstRect.origin.x / widthScaleFactor - srcRect.origin.x;
+      p.y = dstRect.origin.y / heightScaleFactor - srcRect.origin.y;
+
+      DPSgsave(ctxt);
+      DPSrectclip(ctxt, dstRect.origin.x, dstRect.origin.y,
+                  dstRect.size.width, dstRect.size.height);
+      DPSscale(ctxt, widthScaleFactor, heightScaleFactor);
+      [self drawRepresentation: [self bestRepresentationForDevice: nil]
+            inRect: NSMakeRect(p.x, p.y, imgSize.width, imgSize.height)];
+      DPSgrestore(ctxt);
+
+      return;
+    }
+
+  /* We cannot ask the backend to draw the image directly when the source rect 
+     doesn't cover the whole image.
+     Cairo doesn't support to specify a source rect for a surface used as a 
+     source, see cairo_set_source_surface()).
+     CoreGraphics is similarly limited, see CGContextDrawImage().
+     For now, we always use a two step process:
+     - draw the image data in a cache to apply the srcRect to inRect scaling
+     - draw the cache into the destination context
+     It might be worth to move the first step to the backend, so we don't have 
+     to create a cache window but just an intermediate surface.
+     We create a cache every time but otherwise we are more efficient than the 
+     old code path since the cache size is limited to what we actually draw 
+     and doesn't involve drawing the whole image. */
+  {
+    /* An intermediate image used to scale the image to be drawn as needed */
+    NSCachedImageRep *cache;
+    /* The scaled image graphics state we used as the source from which we 
+       draw into the destination (the current graphics context)*/
+    int gState;
+    /* The context of the cache window */
+    NSGraphicsContext *cacheCtxt;
+    /* The size of the cache window that will hold the scaled image */
+    NSSize cacheSize = NSMakeSize(imgSize.width * widthScaleFactor, 
+      imgSize.height * heightScaleFactor);
+    NSRect srcRectInCache = NSMakeRect(srcRect.origin.x * widthScaleFactor, 
+                                      srcRect.origin.y * heightScaleFactor, 
+                                     srcRect.size.width * widthScaleFactor, 
+                                   srcRect.size.height * heightScaleFactor);
+
+    cache = [[NSCachedImageRep alloc]
+                initWithSize: cacheSize
+                       depth: [[NSScreen mainScreen] depth]
+                    separate: YES
+                       alpha: YES];
+
+    [[[cache window] contentView] lockFocus];
+    cacheCtxt = GSCurrentContext();
+
+    /* Clear the cache window surface */
+    DPScompositerect(cacheCtxt, 0, 0, cacheSize.width, cacheSize.height, NSCompositeClear);
+    gState = [cacheCtxt GSDefineGState];
+
+    //NSLog(@"Draw in cache size %@", NSStringFromSize(cacheSize));
+
+    /* We must not use -drawRepresentation:inRect: because the image must drawn 
+       scaled even when -scalesWhenResized is NO */
+    [[self bestRepresentationForDevice: nil] 
+      drawInRect: NSMakeRect(0, 0, cacheSize.width, cacheSize.height)];
+    /* If we're doing a dissolve, use a DestinationIn composite to lower
+       the alpha of the pixels.  */
+    if (delta != 1.0)
+      {
+        DPSsetalpha(cacheCtxt, delta);
+        DPScompositerect(cacheCtxt, 0, 0, cacheSize.width, cacheSize.height,
+                         NSCompositeDestinationIn);
+      }
+
+    [[[cache window] contentView] unlockFocus];
+
+    //NSLog(@"Draw in %@ from %@ from cache rect %@", NSStringFromRect(dstRect), 
+    //  NSStringFromRect(srcRect), NSStringFromRect(srcRectInCache));
+
+    [ctxt GSdraw: gState
+         toPoint: dstRect.origin
+        fromRect: srcRectInCache
+       operation: op
+        fraction: delta];
+
+    [ctxt GSUndefineGState: gState];
+    DESTROY(cache);
+  }
+}
+
+/* Old code path that can probably partially be merged with the new native implementation.
+Fallback for backends other than Cairo. */
+- (void) guiDrawInRect: (NSRect)dstRect
+              fromRect: (NSRect)srcRect
+             operation: (NSCompositingOperation)op
+              fraction: (float)delta
 {
   NSGraphicsContext *ctxt = GSCurrentContext();
   NSAffineTransform *transform;
@@ -1143,6 +1274,21 @@ repd_for_rep(NSArray *_reps, NSImageRep *rep)
   }
 }
 
+- (void) drawInRect: (NSRect)dstRect
+           fromRect: (NSRect)srcRect
+          operation: (NSCompositingOperation)op
+           fraction: (float)delta
+{
+  if ([GSCurrentContext() supportsDrawGState])
+  {
+    [self nativeDrawInRect: dstRect fromRect: srcRect operation: op fraction: delta];
+  }
+  else
+  {
+    [self guiDrawInRect: dstRect fromRect: srcRect operation: op fraction: delta];
+  }
+}
+
 - (void) addRepresentation: (NSImageRep *)imageRep
 {
   GSRepData *repd;

Source/NSImageCell.m

@@ -28,6 +28,7 @@
 
 #include "config.h"
 #include <Foundation/NSDebug.h>
+#include "AppKit/NSAffineTransform.h"
 #include "AppKit/NSCell.h"
 #include "AppKit/NSGraphics.h"
 #include "AppKit/NSImageCell.h"
@@ -197,6 +198,7 @@ scaleProportionally(NSSize imageSize, NSRect canvasRect)
   NSPoint	position;
   BOOL		is_flipped = [controlView isFlipped];
   NSSize  imageSize, realImageSize;
+  NSAffineTransform *xform = nil;
 
   NSDebugLLog(@"NSImageCell", @"NSImageCell drawInteriorWithFrame called");
 
@@ -273,10 +275,13 @@ scaleProportionally(NSSize imageSize, NSRect canvasRect)
     }
 
   // account for flipped views
-  if (is_flipped)
+  if (is_flipped && controlView != nil)
     {
-      position.y += imageSize.height;
-      imageSize.height = -imageSize.height;
+      xform = [NSAffineTransform transform];
+      [xform translateXBy: 0 yBy: [controlView bounds].size.height];
+      [xform scaleXBy: 1 yBy: -1];
+      [xform concat];
+      position.y = [controlView bounds].size.height - position.y - imageSize.height;
     }
 
   // draw!
@@ -286,6 +291,12 @@ scaleProportionally(NSSize imageSize, NSRect canvasRect)
                                     realImageSize.height)
                operation: NSCompositeSourceOver
                fraction: 1.0];
+
+  if (is_flipped && controlView != nil)
+    {
+      [xform invert];
+      [xform concat];
+    }
 }
 
 - (NSSize) cellSize

Source/NSImageRep.m

@@ -453,8 +453,6 @@ implement, so we can't do that. */
   ctxt = GSCurrentContext();
   if (aPoint.x != 0 || aPoint.y != 0)
     {
-      if ([[ctxt focusView] isFlipped])
-	aPoint.y -= _size.height;
       ctm = GSCurrentCTM(ctxt);
       DPStranslate(ctxt, aPoint.x, aPoint.y);
       reset = 1;
@@ -480,8 +478,6 @@ implement, so we can't do that. */
   ctxt = GSCurrentContext();
   scale = NSMakeSize(NSWidth(aRect) / _size.width, 
 		     NSHeight(aRect) / _size.height);
-  if ([[ctxt focusView] isFlipped])
-    aRect.origin.y -= NSHeight(aRect);
   ctm = GSCurrentCTM(ctxt);
   DPStranslate(ctxt, NSMinX(aRect), NSMinY(aRect));
   DPSscale(ctxt, scale.width, scale.height);

Source/NSView.m

@@ -3002,9 +3002,16 @@ in the main thread.
   destPoint = aRect.origin;
   destPoint.x += delta.width;
   destPoint.y += delta.height;
+  if ([self isFlipped])
+    {
+      destPoint.y += aRect.size.height;
+    }
+
+  //NSLog(@"destPoint %@ in %@", NSStringFromPoint(destPoint), NSStringFromRect(_bounds));
 
   [self lockFocus];
-  NSCopyBits(0, aRect, destPoint);
+  //NSCopyBits(0, aRect, destPoint);
+  NSCopyBits([[self window] gState], [self convertRect: aRect toView: nil], destPoint);
   [self unlockFocus];
 }