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Bug 2487 - Suggestion: adding TTF_SetFontSize() to set font size dynamically
Summary: Suggestion: adding TTF_SetFontSize() to set font size dynamically
Status: RESOLVED FIXED
Alias: None
Product: SDL_ttf
Classification: Unclassified
Component: misc (show other bugs)
Version: unspecified
Hardware: All All
: P2 API change
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
: 2486 (view as bug list)
Depends on:
Blocks:
 
Reported: 2014-04-09 13:54 UTC by George Wu
Modified: 2019-01-31 14:01 UTC (History)
2 users (show)

See Also:

Attachments
The TTF_SetFontSize() function. (2.15 KB, text/plain)
2014-04-09 13:54 UTC, George Wu 		Details
patch (1.97 KB, patch)
2018-10-30 19:43 UTC, Sylvain 		Details | Diff
test case (8.05 KB, text/x-csrc)
2018-10-30 19:48 UTC, Sylvain 		Details
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Description George Wu 2014-04-09 13:54:11 UTC 
Created attachment 1612 [details]
The TTF_SetFontSize() function.

In SDL_ttf-2.0.12, the font size cannot be set dynamically. To reset the font, I must close the original font, and load it with a new size again.
This patch suggests an API change of SDL_ttf. It adds a function TTF_SetFontSize(), whose code is uploaded as attachment.
Robustness fixme:
Original height and new height of a font are both integers, the final glyph_italics field (integer) will not be so accurate after re-setting the size many times.
Source:
Fixed from the code on http://blog.csdn.net/fghjkldf/article/details/11562443 (line 77).
Comment 1 Philipp Wiesemann 2014-04-13 18:53:29 UTC 
The TTF_SetFontSize() function uses TTF_CloseFont() on the TTF_Font if there was an error which then also deletes the TTF_Font.
I think this is confusing because I would expect the TTF_Font to be still usable after calling TTF_SetFontSize(). There is no return value which tells me that I can not use it again.

The other TTF_Set*() also do not have return values so maybe a consistent solution would be to have TTF_SetFontSize() set the error message but not delete the TTF_Font. (This assumes that trying to set the font size and failing does not corrupt the TTF_Font in any way.)

To make TTF_SetFontSize() usable it also needs to be added to SDL_ttf.h.

The function TF_SetFontSize() is also available in an attachment at bug 2486.
Comment 2 Sylvain 2018-10-30 19:43:24 UTC 
Created attachment 3418 [details]
patch

Add a patch for this based on head with similar behaviour.
Comment 3 Sylvain 2018-10-30 19:48:43 UTC 
Created attachment 3419 [details]
test case

test case to try it. keyboard o/p to change increase/decrease the font size.
Comment 4 Sylvain 2019-01-31 13:49:22 UTC 
Fixed in ttps://hg.libsdl.org/SDL_ttf/rev/1f3d498496da
Comment 5 Sylvain 2019-01-31 14:01:31 UTC 
*** Bug 2486 has been marked as a duplicate of this bug. ***