Fixed memory leak of font data

[yoshinorisano]

There is a memory leak where font data is handled.
I found it by using _CrtDumpMemoryLeaks() , which is available in Visual Studio.
After applying this change, no memory leak detected.

The memory leak detector reported like this:

Detected memory leaks!
Dumping objects ->
{491} normal block at 0x00000254A12E2070, 9527428 bytes long.
 Data: <ttcf           (> 74 74 63 66 00 02 00 00 00 00 00 04 00 00 00 28 
Object dump complete

[yoshinorisano]

Could you review this?

[ocornut]

Hello,

Thanks for the PR.
This looks incorrect. If font_cfg->FontDataOwnedByAtlas is false we don't claim overship over font_cfg->FontData as it is owned by application and therefore should be freed by the allocation.

(One purpose of this is to allow application to have FontData point to e.g. read-only memory).

[thedemons]

You must set FontDataOwnedByAtlas to false if you were loading the fonts from resources or somewhere in memory that you allocated on your own and not by ImGui, so in this case, it's not a bug

	static const ImWchar rangesAwesome[] = { ICON_MIN_FA, ICON_MAX_FA, 0 };
	ImFontConfig configAwesome;
	configAwesome.MergeMode = true;
	configAwesome.FontDataOwnedByAtlas = false; // don't free memory
	configAwesome.OversampleH = configAwesome.OversampleV = 1;
	fontAtlas->AddFontFromMemoryTTF((void*)fa_solid_900, sizeof(fa_solid_900), 12.f, &configAwesome, rangesAwesome);

[yoshinorisano]

@ocornut @thedemons
Sorry, I didn't understand the usage of the ImFontConfig's FontDataOwnedByAtlas member...
In fact, I did copy & paste some code from somewhere, in that code, FontDataOwnedByAtlas = false was coded.
Now I understand Dear ImGui much more.
Thank you so much!!