Use a transparent image on top of the standard background color of a View - calayer

Question

I' ve a NSOutlineView with a custom background color set with setBackroundColor: method. After that I wan' t to draw a transparent image on top of that background color. I tried with layer but it don' t work. Anyone knows how to do that? thanks

Answer 1

Something like this should work for your case,
Just pasting the relavent code from my application
What i wanted to say is,
You need to make a custom NSOutliveView and override its drawRect,
In case if it wouldn't work in your case, then take a Custom NSView and draw transparent NSOutlineView
- (void)drawRect:(NSRect)rect
{
switch (_backgroundStyle) {
case ImageColorBackgroundStyle:
{
[self drawColor];
[self drawCustomImage:rect];
break;
}
case ColorBackgroundStyle:
[self drawColor];
break;
case PatternBackgroundStyle:
[self drawPattern];
break;
case ImageBackgroundStyle:
[self drawImage];
break;
case GradientBackgroundStyle:
[self drawGradient];
break;
case NoBackgroundStyle:
if([self hasBorder])
[self drawBorder:rect];
return;
[[NSColor clearColor] set];
NSRectFill(rect);
break;
default:
[super drawRect:rect];
break;
}
if([self hasBorder])
[self drawBorder:rect];
}
-(void)drawCustomImage:(NSRect)rect{
NSRect boundsRect = [self bounds];
NSRect imageRect;
NSSize imageSize = [pBGroundImage size];
int x=0;int y=0;
switch (bgImagePosition) {
case img_bg_lowerright:
if(bViewClipped) return;
x = boundsRect.size.width - imageSize.width;
x -= (BORDER_WIDTH*2);
break;
default:
if(!bViewClipped)
return [self drawImage];
break;
}
if(!bViewClipped)
imageRect = NSMakeRect(x,y,imageSize.width,imageSize.height);
else {
imageRect = NSMakeRect(x,y,rect.size.width,rect.size.height);
}
if(imageRect.origin.x < 0 ) imageRect.origin.x = 0;
if(!bViewClipped){
[pBGroundImage drawInRect:imageRect fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
}
else {
CGFloat x_Res = 0.0f;
CGFloat y_Res = 0.0f;
x_Res = orignalSize.width/imageSize.width;
y_Res = orignalSize.height/imageSize.height;
CGFloat scaledHeight = orignalSize.height - rect.size.height;
CGFloat orignal_y = scaledHeight/y_Res;
CGFloat orignal_width = imageSize.height - orignal_y;
NSRect srcRect;
/* This is wrt Orignal Image */
srcRect.origin.x = 0;
srcRect.origin.y = orignal_y;
srcRect.size.width = imageSize.width;
srcRect.size.height = orignal_width;
[pBGroundImage drawInRect:rect
fromRect:srcRect
operation:NSCompositeSourceOver fraction:1.0];
}
}
- (void)drawImage
{
// Load the image.
//NSString *imageName = [self GetBackGroundImage];
//NSImage *anImage = [[NSImage alloc ]initByReferencingFile:imageName];
// Find the point at which to draw it.
NSPoint backgroundCenter;
backgroundCenter.x = [self bounds].size.width / 2;
backgroundCenter.y = [self bounds].size.height / 2;
NSPoint drawPoint = backgroundCenter;
drawPoint.x -= [pBGroundImage size].width / 2;
drawPoint.y -= [pBGroundImage size].height / 2;
[pBGroundImage drawInRect:[self bounds] fromRect:NSZeroRect operation:NSCompositeSourceOver fraction:1.0];
//[anImage release];
}