Colouring fonts

Hi!

I don’t understand how to change colour for Font_Paint. I can see that there are a number of swis, but all I get is black. Can anyone give me a example?

I am running in 256 colours.

Fireworkz and PipeDream both use SWI ColourTrans_SetFontColours(0, fg_rgb, bg_rgb, 14)

IN what format is rgb specified. I do like the way you write, except for r0 wich I point to my fonthandle. The handle is ok, I am using it in font_paint.
I still only get black text.

IN what format is rgb specified.

PRM 3-338:

The palette entry is a word of the form &BBGGRR00. That is, it consists of four bytes, with the palette value for the blue, green and red gun in the top three bytes. Bright white, for instance would be &FFFFFF00, while half intensity cyan would be &77770000. The current graphics hardware only uses the upper nibbles of these colours, but for upwards compatibility the lower nibble should contain a copy of the upper nibble.

red gun …

The current graphics hardware only uses the upper nibbles of these colours

Oh, the poor PRMs do need some TLC!

The palette entry is a word of the form &BBGGRR00. T

Thats what I have. Still black text. I wonder if it can be font related. I have tried Homerton and Trinity,

Oh, the poor PRMs do need some TLC!

Is there any mention in 5a?

Is the font handle being correctly passed to each call? Don’t rely upon “current font” unless you’re the only thing running (as a full screen app).

Another factor: I paint text to a 8-bit sprite. I am also drawing with OS_Plot and can change gcol for that.

Are you doing the ColourTrans_SetFontColours immediately before the Font_Paint, i.e. after setting the sprite as output?

And set up a save area; do not rely upon the default system save area as FontManager can redirect itself when caching fonts…

If you are struggling to make something work, produce a minimal example to see how it functions. Then you can use that as a small worked example to play with different parameters, and you won’t be confused by trying to make things work en masse. Apply the same mentality you would for testing, of checking the behaviour in its smallest parts to be sure you understand what’s going on. And if you’re not thinking about testing, those small examples that you made to debug things can become your tests. If you’re still stuck, your minimal example will be small enough to include when you explain what the problem is on public forums.

And I’ve produced some examples of how you use some of the RISC OS APIs. https://github.com/gerph/riscos-examples/blob/master/graphics/fonts/FontPaint%2Cfd1 for example.

Turned out to be a casting error. In one of the SpriteOp swis I managed to write (int) instead of (unsigned int) when pointing out the sprite area.. GAH!

But happy that it works and good that I got the opportunity to learn more about fonts!