This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• patch (measure.patch, text/plain, 2019-02-20 16:56:39 +0000, 6102 bytes)
• updated patch (measure2.patch, text/plain, 2019-02-22 18:55:16 +0000, 6147 bytes)

Reported in version: unspecified
Reported for operating system, platform: All, All

Comments on the original bug report:

On 2019-02-20 16:56:39 +0000, Dmitry Gapkalov wrote:

Created attachment 3641
patch

/* Get the measurement string of text without rendering
in:
width - in pixels to measure this text
out:
result - latest position in text inside width
extent - latest calculated width(more or equal to width)
*/
extern DECLSPEC int SDLCALL TTF_MeasureText(TTF_Font *font, const char *text, int width, int *extent);
extern DECLSPEC int SDLCALL TTF_MeasureUTF8(TTF_Font *font, const char *text, int width, int *extent);
extern DECLSPEC int SDLCALL TTF_MeasureUNICODE(TTF_Font *font, const Uint16 *text, int width, int *extent);

On 2019-02-22 14:17:21 +0000, Sylvain wrote:

Hey, thanks for the patch !

So this function gives the maximum of char that can fit in 'width' pixel.

Just wondering, why is this function needed ?
It seems like re-doing the SDL_ttf Wrap function ?

On 2019-02-22 16:12:15 +0000, Dmitry Gapkalov wrote:

For algorithm like:

• auto add "..." in the end of the line
• auto-text height for specific bounds

SDL_ttf Wrap spend time for rendering text, but need calculation
first.

On 2019-02-22 18:55:16 +0000, Dmitry Gapkalov wrote:

Created attachment 3650
updated patch

updated version of patch

On 2019-02-22 20:06:16 +0000, Sylvain wrote:

Not sure I got it, so I've more questions:

If you want to add "...", why don't you string cat it as a suffix ? Then render ?

"- auto-text height for specific bounds", you mean a Wrap function with user defined height ?
-> that would be a TTF_SetLineSkip() ?

But I think this mesure functionnality is interesting for re-writing the wrap lenght algorithm which call to many times TTF_SetSize()
( https://discourse.libsdl.org/t/optimization-suggestion-for-sdl-ttf-on-long-paragraphs/25777 )

On 2019-02-25 16:14:40 +0000, Dmitry Gapkalov wrote:

1. If you want to add "...", why don't you string cat it as a suffix ? Then render ?

I have maximum width(in pixels) and font size, I need put text, and if some text not included, I need to put '...' in the end of the line. I need to calculate how many symbols I can put before "...".

2. "- auto-text height for specific bounds", you mean a Wrap function with user defined height ?
   -> that would be a TTF_SetLineSkip() ?

Wrapped function in SDL is just for simple text rendering. It not cover real cases like html-css view.

On 2019-03-25 13:59:56 +0000, Sylvain wrote:

I've added the API, a little bit modified, here:
https://hg.libsdl.org/SDL_ttf/rev/eb1d2358c50c

Together with changing the _Wrapped functions, which are good candidates to use it.

Can you check it ?

What is different:

• it returns the usual -1/0 upon success.
• the "result" is an output parameter.

I don't returns the extent as:
SDL_max(maxx, FT_FLOOR(x + prev_advance)) - minx;
but:
maxx - minx
Not to forward what seems added for a corner case ..

Also, maybe it would be interesting to have more parameters for the measurement :

• prior_character The optionally-specified character that immediately precedes the string. This may have an impact on the string width due to kerning
  (eg https://github.com/libRocket/libRocket/blob/master/Source/Core/FreeType/FontFaceHandle.h#L70 )
• extent_height ?
• advance width/height ?

On 2019-04-12 14:53:04 +0000, Dmitry Gapkalov wrote:

Hello, sorry for long delay.

Yes your solution looks perfect, except one thing, please modify this part:

    /* Measurement mode */
    if (measure_width) {
        int cw = maxx - minx;
        if (cw >= measure_width) {
            break;
        }
  current_width = cw;
  char_count += 1;
    }

Current width for result needed from previous calculation, because our task is insert some text in max width.

On 2019-04-12 19:34:22 +0000, Sylvain wrote:

Hello,

Thanks for checking! I've modified it:
https://hg.libsdl.org/SDL_ttf/rev/fd1e90b8cfca

On 2019-04-12 19:53:48 +0000, Dmitry Gapkalov wrote:

Thank you so much. Done.

On 2019-04-22 17:42:40 +0000, Dmitry Gapkalov wrote:

Hello, need additional fix:

   /* Measurement mode */
    if (measure_width) {
  int cw = SDL_max(maxx, FT_FLOOR(x + prev_advance)) - minx;
        if (cw >= measure_width) {
            break;
        }
  current_width = cw;
  char_count += 1;
    }

I return previous version of calculation cw, because current variant:

int cw = maxx - minx;

doesn't correct measure strings ended with more than one space at the end.

On 2019-04-23 12:21:25 +0000, Sylvain wrote:

Fixed https://hg.libsdl.org/SDL_ttf/rev/8be7bd6ac3d0
Thanks !