Re: Re: Creating an NSImage from a bitmap

FROM : Craig Dooley
DATE : Thu Aug 10 21:45:13 2006

Actually, to correct myself, I don't need to flip the alpha.  I was
compositing it incorrectly.  Thanks for the help.

-Craig

On 8/10/06, Hidetomo Katsura <<email_removed>> wrote:
> make sure to let the mailing list know that it worked. :)
>
> regards,
> katsura
>
> On Aug 10, 2006, at 12:17 PM, Craig Dooley wrote:
>
> > You're right.  I think I got it working by flipping the alpha, and
> > using NSCompositeDestinationAtop.  I don't know where I got that from,
> > but that's for fixing that for me.
> >
> > -Craig
> >
> > On 8/10/06, Hidetomo Katsura <<email_removed>> wrote:
> >> you are welcome. fyi, it works with the same pattern for both black
> >> and alpha. i forgot to mention that you need to use
> >> NSCompositeSourceOver (not NSCompositeCopy) to draw the image if you
> >> want to use alpha.
> >>
> >> regards,
> >> katsura
> >>
> >> On Aug 10, 2006, at 11:39 AM, Craig Dooley wrote:
> >>
> >> > Thanks guys.  That works if I copy the pattern and bitswap it
> >> for the
> >> > alpha channel.
> >> >
> >> > On 8/10/06, Hidetomo Katsura <<email_removed>> wrote:
> >> >> Craig,
> >> >>
> >> >> this seems to work. you need to use an alpha plane and
> >> hasAlpha:YES
> >> >> if you want a transparent center.
> >> >>
> >> >> - (NSImage *)black16x16SquareImage
> >> >> {
> >> >>        static unsigned char pattern[] =
> >> >>        {
> >> >>                0xff, 0xff,
> >> >>                0xff, 0xff,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xc0, 0x03,
> >> >>                0xff, 0xff,
> >> >>                0xff, 0xff
> >> >>        };
> >> >>
> >> >>        NSBitmapImageRep *glyph;
> >> >>        NSImage *image;
> >> >>        unsigned char *planes[ 2 ];
> >> >>
> >> >>        planes[ 0 ] = pattern;  // black
> >> >>        planes[ 1 ] = pattern;  // alpha
> >> >>        glyph = [[NSBitmapImageRep alloc]
> >> >> initWithBitmapDataPlanes:&planes[ 0 ]
> >> >>                                pixelsWide:16
> >> >>                                pixelsHigh:16
> >> >>                                bitsPerSample:1
> >> >>                                samplesPerPixel:2
> >> >>                                hasAlpha:YES
> >> >>                                isPlanar:YES
> >> >>
> >> >> colorSpaceName:NSDeviceBlackColorSpace
> >> >>                                bytesPerRow:2
> >> >>                                bitsPerPixel:0];
> >> >>        image = [[NSImage alloc] initWithSize:NSMakeSize( 16,
> >> 16 )];
> >> >>        [image addRepresentation:glyph];
> >> >>
> >> >>        return [image autorelease];
> >> >> }
> >> >>
> >> >> regards,
> >> >> katsura
> >> >>
> >> >> On Aug 10, 2006, at 9:01 AM, Craig Dooley wrote:
> >> >>
> >> >> > I am attempting to take a bitmap, and generate a black/
> >> transparent
> >> >> > NSImage from it.  The following example is attempting to draw a
> >> >> 16x16
> >> >> > square in black, that is transparent in the center.  It does
> >> >> create a
> >> >> > 16x16 NSImage, which i can display, but only the top line and
> >> one
> >> >> > pixel on the second row are black, and the rest is white.  Is
> >> there
> >> >> > any way to do this, or do i need to translate the data to
> >> another
> >> >> > format first?
> >> >> >
> >> >> > unsigned char pattern[] = {
> >> >> >      0xff, 0xff,
> >> >> >      0xff, 0xff,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xc0, 0x03,
> >> >> >      0xff, 0xff,
> >> >> >      0xff, 0xff
> >> >> > };
> >> >> >
> >> >> > unsigned char *planes[] = ;
> >> >> > glyph = [[NSBitmapImageRep alloc]
> >> initWithBitmapDataPlanes:planes
> >> >> >                      pixelsWide:16
> >> >> >                      pixelsHigh:16
> >> >> >                      bitsPerSample:1
> >> >> >                      samplesPerPixel:1
> >> >> >                      hasAlpha:NO
> >> >> >                      isPlanar:NO
> >> >> >                      colorSpaceName:NSDeviceBlackColorSpace
> >> >> >                      bytesPerRow:0
> >> >> >                      bitsPerPixel:0];
> >> >> > image = [[NSImage alloc] init];
> >> >> > [image addRepresentation:glyph];
> >> >> >
> >> >> > -Craig
> >> >>
> >> >
> >> >
> >> > --
> >> >
> >> ---------------------------------------------------------------------
> >> -
> >> > -
> >> > Craig Dooley <<email_removed>>
> >>
> >>
> >
> >
> > --
> > ----------------------------------------------------------------------
> > -
> > Craig Dooley <<email_removed>>
>
>



--
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Craig Dooley <<email_removed>>