Just Draw Text™

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README.md

dtext

dtext is a font-rendering library that aims at simplicity, both of the internals and of use.

Installation

In order to use dtext in one of your projects, the recommended way is to just drop dtext.h and dtext.c in its directory and add them to the Makefile. For legal matters, despite this not being legal advice, you most likely should in this case add anyone noted as owning a copyright for this code in the LICENSE file to the place you keep your own list.

You can also build dtext as a shared library, and then link against it. This should relieve you of the obligation of adding names to your copyright list, so long as you do not distribute both files bundled. Again, this is not legal advice.

Usage

Most functions return a dt_error value. In this case, zero means success and any non-zero value indicates failure.

dt_error dt_init(dt_context **ctx, Display *dpy, Window win);
void dt_quit(dt_context *ctx);

First, you need to initialize the library using dt_init. At the end of the program, you should close it with dt_quit.

dt_error dt_load(dt_context *ctx, dt_font **fnt, char const *name)
void dt_free(dt_context **ctx, dt_font *fnt);

Then, you can load fonts using dt_load, and free them with dt_free. The format of the name argument is described in the "Font names" section below.

dt_error dt_box(dt_context *ctx, dt_font *fnt, dt_bbox *bbox,
                wchar_t const *txt, size_t len);
dt_error dt_draw(dt_context *ctx, dt_font *fnt, dt_color const *color,
                 uint32_t x, uint32_t y, wchar_t const *txt, size_t len);

These are the two main functions of the library.

dt_box returns a bounding box to the string composed of the first len characters of txt, drawn with font fnt. The return is done through the pointer bbox, which will contain the bounding box. bbox->x and bbox->y will contain the coordinates of the top-left corner of the box relative to the origin of the baseline, and bbox.w and bbox.h are its width and height.

dt_draw draws the string composed of the first len characters of txt, drawn with font fnt, in color color, with the baseline starting at position x, y.

dt_color represents a color. It is of the form { .red, .green, .blue, .alpha }, with alpha = 0xFF for full-visibility. For example, if it is memset with 0xFF, it will be the color "white".

The baseline is the line on which text would be drawn, if it was drawn by hand. dt_font.ascent is the height of the highest character of the font, relative to the baseline. dt_font.height is the total height of the highest character in the font.

Font names

A font name is composed of several font descriptions, separated by ;. Each font description is a file name and a pixel size, separated by :.

For example, the following is a valid font string:

/fonts/main.ttf:16;/fonts/special_chars.ttf:18;/fonts/fallback.ttf:16

You have to specify one font size per font file, given every font file is not built the same way.

Examples

You can find examples in the examples directory. They have been built using certain fonts you may not have ; so you may have to edit the font strings located near the top of those files.

In order to test them, just run make and run the executables in build/.

Distribution

This code is distributed at https://git.ekleog.org/leo/dtext ; and every commit should be signed with OpenPGP key

AA29 BF0D F468 A8DC 1AB0  EA84 6598 F235 F23F B2AE

If this is not the case, it means either I forgot to sign a commit, or you are getting MitM-ed. In any case, please do not use code from an unsigned version without properly checking it.

Contributing

Please send any comments, insults or preferably patches to dtext@leo.gaspard.io .