开罗字体渲染中消失的字符

发布于 2024-08-22 07:00:10 字数 729 浏览 7 评论 0原文

我使用 cairo 将简单的文本渲染到 cairo 表面上。我使用 freetype 字体（Vera.ttf，如果重要的话）。它有效，但有时字符会从输出中消失。事实上只是数字。我画了一个文本“Demostream 1..”，有时“1”从输出中消失，我完全不知道为什么。该数字绝对是字符串的一部分。也不存在记忆损坏或类似的情况。这是绘制文本的代码：

font = cairo_ft_font_face_create_for_ft_face(ftFace, 0);
cr = cairo_create(surface);

/* set the foreground color */
cairo_set_source_rgba(cr, ...);

/* render the text */
cairo_set_antialias(cr, CAIRO_ANTIALIAS_GRAY);
cairo_set_font_face(cr, font);
cairo_set_font_size(cr, size);
cairo_move_to(cr, x, y);

cairo_show_text(cr, text);

cairo_destroy(cr);
cairo_font_face_destroy(font);

ftFace 是加载的 freetype 字体。

我也会使用 pango 来渲染文本，但我没有可用的字体缓存 - 所以我不知道如何将字体加载到 pango 中，因为它显然只支持字体缓存，不支持直接字体加载。

欢迎任何输入..

原文

I use cairo to render a simple text onto a cairo surface. I use a freetype font for that (Vera.ttf if that matters). It works, but sometimes characters disappear from the output. In fact only the numbers. I drew a text 'Demostream 1..' and sometimes the '1' disappears from the output and I have absolutely no idea why. The number is defitivly part of the string. There's also no memory corrpution or anything like that. This is the code that draws the text:

font = cairo_ft_font_face_create_for_ft_face(ftFace, 0);
cr = cairo_create(surface);

/* set the foreground color */
cairo_set_source_rgba(cr, ...);

/* render the text */
cairo_set_antialias(cr, CAIRO_ANTIALIAS_GRAY);
cairo_set_font_face(cr, font);
cairo_set_font_size(cr, size);
cairo_move_to(cr, x, y);

cairo_show_text(cr, text);

cairo_destroy(cr);
cairo_font_face_destroy(font);

ftFace is a loaded freetype font face.

I also would use pango to render the text, but I don't have fontcache available - so I have no idea howto load the Font into pango since it obviously only supports fontcache and no direct font loading.

Any input is welcome..

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