[jonsaunders]

When using NSRectFill with a colour set with an alpha component, the fill rect is not transparent, but if I use a NSBezierPath the rect is transparent.

thus

<BLOCKQUOTE><font size="1"face="Geneva, Verdana, Arial">code:</font><HR><pre><font size=1 face=courier>
-(void)drawRect NSRect*) aRect
{
[[[NSColor whiteColor] colorWithAlphaComponent:<font color = blue>0.5</font>] set];
NSRectFill(aRect)
</font>[/code]

... no transparency...

but

<BLOCKQUOTE><font size="1"face="Geneva, Verdana, Arial">code:</font><HR><pre><font size=1 face=courier> -(void)drawRect NSRect*) aRect
{
NSBezierPath *path;
[[[NSColor whiteColor] colorWithAlphaComponent:<font color = blue>0.5</font>] set];
path = [NSBezierPath bezierPathWithRect:aRect];
[path fill];
</font>[/code]
...draws transparent...

Does anyone know if there is a reason for this or is it a bug?

Cheers,

Jon

[lindberg]

I think NSRectFill() uses NSCompositeCopy (i.e. replace the existing color) when drawing. I've not actually done this myself, but you might want to try NSRectFillUsingOperation() using NSCompositeSourceOver as the operation.

[jonsaunders]

That works! Cheers!

Now I am having fun with images made up from data from drawn NSViews. The only problem is that I get a black background for my images and cannot get rid of it

<BLOCKQUOTE><font size="1"face="Geneva, Verdana, Arial">code:</font><HR><pre><font size=1 face=courier>
- (void)drawRect NSRect)rect
{
NSRect xrect;
NSBezierPath* path;

[[NSColor clearColor] set];
path = [NSBezierPath bezierPathWithRect:rect];
[path fill];

xrect = NSMakeRect(<font color = blue>10</font>,<font color = blue>10</font>,<font color = blue>10</font>,<font color = blue>10</font>);

[[NSColor redColor] set];

NSRectFill(xrect);
}

-(NSImage*)imageData
{
return [[NSImage alloc] initWithData:[self dataWithPDFInsideRect:[self bounds]]];
}

</font>[/code]

in my back view and

<BLOCKQUOTE><font size="1"face="Geneva, Verdana, Arial">code:</font><HR><pre><font size=1 face=courier>

backView = [[WSBackView alloc] initWithFrame:aRect];
image = [backView imageData];

[image compositeToPoint:NSMakePoint(<font color = blue>0</font>,<font color = blue>0</font>) operation:NSCompositeSourceOver];

</font>[/code]

in the drawRect of my visible view. I am stuck with a black background..

Any Ideas?

Jon.

[jonsaunders]

I've now sorted it!

I've been doing completely the wrong thing in using a hidden NSView (but I am new to Cocoa!). The correct way is to use a NSCustomImageRep with a delegate draw function. See the CompositeLab sample app in the apple developer samples if you want to know how..

(I am adding this post so that anyone else having the same problems will not fall into the same trap).

Also if you get a strange set of errors with NSCalibratedWhiteColor involved it may be due to you not returning self back from an initWithFrame...

Still having fun,

Jon.