Dark windows and font blending

I’ve got some icons on a window with a dark tiled background, but the outline fonts in the icons are drawn to blend to a light background, which makes them look meh.

One icon has custom large font and a validation string of F70 to set the background and foreground colours, the other icons have the desktop font and foreground and background colours of 0 and 7. The window has a background colour of 1 so a tile sprite is used. The icons seem to be blending to the window background colour of 1 (light grey, despite tiling being used) rather than their assigned background colours, this can be confirmed by setting the background of the window to 7 (black), which gives the correct font blending, but then the window isn’t tiled by the Wimp.

I’ve tried !SpecialFX to enable background font blending for the application, but it doesn’t seem to work unless font blending is enabled for all applications. This make it look great and is what I’m after, but not for the whole desktop as certain applications which over draw text wont work correctly.

Is there any way to make the fonts in the icons have a blend to the icon’s background colour, without globally enabling background font blending?

It’s been 21 years since I did any RISC OS UI stuff, I was hoping someone could remember how it works :(

I might be misremembering, but can’t you use tiles assigned to any of the 16 Wimp colours? So Tile_1 to overlay on Wimp Colour 1, Tile_7 to overlay on a black background?

Thanks Chris, that was exactly it.

As the background tile is closest to colour 6, I renamed it tile_6 and set the window background to 6, and now the font blending is now perfect.

I don’t know if it is related (probably not), but font blending, or actually anti-aliasing, doesn’t always work properly on my 4té with RISC OS 5.29. Here’s an example of a Homerton Bold font on a coloured background in an icon (3x zoom):

Not only anti-aliasing appears to be switched off completely, also the horizontal spacing doesn’t work properly, while both are configured to 120 points and 100 points respectively. (The font is at 16 point.)

The same icon on my ARMiniX, with RISC OS 5.23, and with the same configuration settings looks like it should be:

Is this a known issue, or have a missed something?

Well, my problem seems to be font blending related after all and appears to be similar to what Druck described. So, contrary to what I wrote, the example above is not an outline font in an icon with a coloured background, it’s an outline font in a transparent icon on top of another icon with a filled colour. However, contrary to what Druck described, I can specify the program in !SpecialFX, without enabling font blending for all applications.

It solves the problem, but leaves the question why such action is needed in RISC OS 5.29, while in RISC OS 5.23 it works right away.

Are you sure that you haven’t turned on !SpecialFX on the RISC OS 5.23 machine? As it shouldn’t be able to blend to an unrelated background without it.

Are you sure that you haven’t turned on !SpecialFX on the RISC OS 5.23 machine?

Absolutely. !SpecialFX isn’t even installed on my ARMiniX. Could it be that? Should I de-install !SpecialFX, that came with my 4té? After all, most of the programs that it appears to take care of, such as Vantage, Fresco, WordWorks, Impression etc., are either abandoned by me ages ago, or even never used at all.

Well, removing !SpecialFX from my 4té didn’t solve the problem. On the contrary, font blending is faulty again.

So the question is: why do I need !SpecialFX on my 4té with RO 5.29 for accurate font blending in specified apps, while my ARMiniX with RO 5.23 blends everything nicely with no !SpecialFX at all?

Paul, is there any chance you could knock up an example program exhibiting this problem? So anyone able to run RISC OS version between 5.23 and 5.29 can see if there is any change in behaviour.

BTW are you using any graphics acceleration on the ARMiniX?

BTW are you using any graphics acceleration on the ARMiniX?

Not that I know of. I didn’t even know that such accelerators exist.
I haven’t yet had the time to knock up an example program, but I discovered that what I wrote in my second post isn’t right either. It’s all about a single icon with text (Homerton Bold) on a white background. So far so good. The colour however is generated in a redraw routine. Only then the blending goes wrong – on my 4té, not on my ARMiniX.