al_draw_text(...) not accurate

fallenlight12

The problem I'm having is... Well, here's the code:

#SelectExpand
  1ALLEGRO_FONT *font = al_load_ttf_font("octovill.ttf",30,0 );
  2if (!font){
  3   LOG("...could not load 'octovill.ttf'.\nEnd Program.", true);
  4   kill_allegro();
  5   return -1;
  6}
  7int txtx, txty, txtw, txth;
  8al_get_text_dimensions(font, "Press ESC to exit program.", &txtx, &txty, &txtw, &txth);
  9al_draw_text(font, al_map_rgb(190,225,190), 0, 0, 0, "Press ESC to exit program.");

The text should appear at 0,0 at the top-left of screen. It does. Its x-position is accurate, but its y-position is +2 in error.

Additionally, al_get_text_dimensions(...) returns an erroneous y offset and a height that's greater than what it should be. The width and x offset it returns are accurate.

The reason I have to come here and ask is because if I don't figure out why it does this then I'll have to write some code to examine the font myself and get the correct x/y offset/width/height for each font type.

If that wasn't enough, I also have to report that when I use ALLEGRO_ALIGN_CENTRE in al_draw_text(...) it centers correctly horizontally but not vertically. In fact, I don't think it even tries to center vertically.

So there appears to be some screwy vertical/y-axis bugs.

On the plus-side, if I can't fix this then I can just convert some win32 code I wrote over to allegro - all i gotta do is replace gdi calls with allegro. (I was loading my fonts from bitmap files.)

I'm using Allegro 5.0.7 binaries.

Peter Wang

Don't know about the y offset. Perhaps it is part of the font?

ALLEGRO_ALIGN_LEFT/CENTRE/RIGHT only align horizontally.

Kris Asick

Most TTF fonts are not pixel-perfect. You'll almost certainly have to adjust your coordinates to take into account the nuances of each font you use.

Elias

Do you have a screenshot and is that .ttf available somewhere?

Thread #611363. Printed from Allegro.cc