labwc/include/scaled-buffer/scaled-font-buffer.h

76 lines
2.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
#ifndef LABWC_SCALED_FONT_BUFFER_H
#define LABWC_SCALED_FONT_BUFFER_H
#include "common/font.h"
struct wlr_scene_tree;
struct wlr_scene_buffer;
struct scaled_buffer;
struct scaled_font_buffer {
struct wlr_scene_buffer *scene_buffer;
int width; /* unscaled, read only */
int height; /* unscaled, read only */
/* Private */
char *text;
int max_width;
float color[4];
float bg_color[4];
struct font font;
struct scaled_buffer *scaled_buffer;
/*
* The following fields are used only for the titlebar, where
* the font buffer can be rendered with a pattern background to
* support gradients. In this case, the font buffer is also
* padded to a fixed height (with the text centered vertically)
* in order to align the pattern with the rest of the titlebar.
*/
int fixed_height;
cairo_pattern_t *bg_pattern; /* overrides bg_color if set */
};
/**
* Create an auto scaling font buffer, providing a wlr_scene_buffer node for
* display. It gets destroyed automatically when the backing scaled_buffer
* is being destroyed which in turn happens automatically when the backing
* wlr_scene_buffer (or one of its parents) is being destroyed.
*
* To actually show some text, scaled_font_buffer_update() has to be called.
*
*/
struct scaled_font_buffer *scaled_font_buffer_create(struct wlr_scene_tree *parent);
/**
* Create an auto scaling font buffer for titlebar text.
* The font buffer takes a new reference to bg_pattern.
*
* @param fixed_height Fixed height for the buffer (logical pixels)
* @param bg_pattern Background pattern (solid color or gradient)
*/
struct scaled_font_buffer *
scaled_font_buffer_create_for_titlebar(struct wlr_scene_tree *parent,
int fixed_height, cairo_pattern_t *bg_pattern);
/**
* Update an existing auto scaling font buffer.
*
* No steps are taken to detect if its actually required to render a new buffer.
* This should be done by the caller to prevent useless recreation of the same
* buffer in case nothing actually changed.
*
* Some basic checks could be something like
* - truncated = buffer->width == max_width
* - text_changed = strcmp(old_text, new_text)
* - font and color the same
*
* bg_color is ignored for font buffers created with
* scaled_font_buffer_create_for_titlebar().
*/
void scaled_font_buffer_update(struct scaled_font_buffer *self, const char *text,
int max_width, struct font *font, const float *color,
const float *bg_color);
#endif /* LABWC_SCALED_FONT_BUFFER_H */