Transparent buffered bitmap

I wrote the code

        gB = new Gfx.BufferedBitmap({
            :disableTransparency => false,
            :width=>(center - goWidth)*2,
            :height=>(center - goWidth)*2,
            :palette=> [
                Gfx.COLOR_BLACK,
                Gfx.COLOR_WHITE,
                Gfx.COLOR_TRANSPARENT
            ]
        });
        var tdc=gB.getDc();
        tdc.setColor(Gfx.COLOR_TRANSPARENT,Gfx.COLOR_TRANSPARENT);
        tdc.clear();

On the last line "tdc.clear()", the simulator freezes.

I planned to overlay this over the background so as not to render the background elements in the bitmap. How do I make this work?

bine8x8 over 6 years ago

Bump

Former Member over 6 years ago

What you are attempting to do is not something that has generally been supported. I think the operations you have listed may have been enabled in a recent SDK update, or may be coming in a later update if not. I am not sure why you would be seeing a simulator freeze.

A workaround that should work even on older SDKs is to use a placeholder color instead of transparent, clear the buffer with that placeholder, and then re-assign the palette with transparent at that index.

xberzerker over 2 years ago in reply to Former Member

could you example the reassign part?

bine8x8 over 2 years ago in reply to Former Member

Ok,

I can reassign one of the colors in the fixed color palette.

        var mask = bufferedBitmapFactory(
        {
            :width=>w+w+4,
            :height=>w+w+4,
            :palette=> [
                $.BGC,
                Graphics.COLOR_WHITE
            ]
        });
... 
        mask.setPalette([
            $.BGC,
            Graphics.COLOR_TRANSPARENT,
        ]);

But how do I reassign one of the colors in the full color palette?

I need to display an image while keeping the image in the background. Since this is done in the native watchface FR965.

        var mask = bufferedBitmapFactory(
        {
            :width=>w+w+4,
            :height=>w+w+4,
        });
... 
        ???????????????????
        mask.setPalette([
            $.BGC,
            Graphics.COLOR_TRANSPARENT,
        ]);
        ???????????????????