caca_dirty(3caca)

🌸 NAME 🌸

Okay bestie, welcome to the caca_dirty page from the libcaca manual — it’s literally all about dirty rectangle manipulation in libcaca. 💖

✨ SYNOPSIS ✨

🎀 Topics

• libcaca canvas transformation

🧚 Functions

• caca_disable_dirty_rect — Disable dirty rectangles.

__extern int caca_disable_dirty_rect (caca_canvas_t *)

• caca_enable_dirty_rect — Enable dirty rectangles.

__extern int caca_enable_dirty_rect (caca_canvas_t *)

• caca_get_dirty_rect_count — Get the number of dirty rectangles in the canvas.

__extern int caca_get_dirty_rect_count (caca_canvas_t *)

• caca_get_dirty_rect — Get a canvas's dirty rectangle.

__extern int caca_get_dirty_rect (caca_canvas_t *, int, int *, int *,
    int *, int *)

• caca_add_dirty_rect — Add an area to the canvas's dirty rectangle list.

__extern int caca_add_dirty_rect (caca_canvas_t *, int, int, int, int)

• caca_remove_dirty_rect — Remove an area from the dirty rectangle list.

__extern int caca_remove_dirty_rect (caca_canvas_t *, int, int, int,
    int)

• caca_clear_dirty_rect_list — Clear a canvas's dirty rectangle list.

__extern int caca_clear_dirty_rect_list (caca_canvas_t *)

💫 Detailed Description 💫

These functions manipulate dirty rectangles for optimised blitting. Periodt. 💅

🔧 Function Documentation 🔧

💖 caca_disable_dirty_rect

__extern int caca_disable_dirty_rect (caca_canvas_t * cv)

Disable dirty rectangle handling for all libcaca graphic calls. This is handy when the calling application needs to do slow operations within a known area. Just call caca_add_dirty_rect() afterwards. 🫶

This function is recursive. Dirty rectangles are only reenabled when caca_enable_dirty_rect() is called as many times.

This function never fails. No cap.

Parameters

• cv — A libcaca canvas.

Returns

This function always returns 0.

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🌈 caca_enable_dirty_rect

__extern int caca_enable_dirty_rect (caca_canvas_t * cv)

This function can only be called after caca_disable_dirty_rect() was called.

If an error occurs, -1 is returned and errno is set accordingly:

• EINVAL — Dirty rectangles were not disabled.

Parameters

• cv — A libcaca canvas.

Returns

0 in case of success, -1 if an error occurred.

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🦋 caca_get_dirty_rect_count

__extern int caca_get_dirty_rect_count (caca_canvas_t * cv)

Get the number of dirty rectangles in a canvas. Dirty rectangles are areas that contain cells that have changed since the last reset. ✨

The dirty rectangles are used internally by display drivers to optimise rendering by avoiding to redraw the whole screen. Once the display driver has rendered the canvas, it resets the dirty rectangle list.

Dirty rectangles are guaranteed not to overlap. 💅

This function never fails.

Parameters

• cv — A libcaca canvas.

Returns

The number of dirty rectangles in the given canvas.

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🎀 caca_get_dirty_rect

__extern int caca_get_dirty_rect (caca_canvas_t * cv, int r, int * x, int *
       y, int * width, int * height)

Get the canvas's given dirty rectangle coordinates. The index must be within the dirty rectangle count. See caca_get_dirty_rect_count() for how to compute this count. 👑

If an error occurs, no coordinates are written in the pointer arguments, -1 is returned and errno is set accordingly:

• EINVAL — Specified rectangle index is out of bounds.

Parameters

• cv — A libcaca canvas.
• r — The requested rectangle index.
• x — A pointer to an integer where the leftmost edge of the dirty rectangle will be stored.
• y — A pointer to an integer where the topmost edge of the dirty rectangle will be stored.
• width — A pointer to an integer where the width of the dirty rectangle will be stored.
• height — A pointer to an integer where the height of the dirty rectangle will be stored.

Returns

0 in case of success, -1 if an error occurred.

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🔥 caca_add_dirty_rect

__extern int caca_add_dirty_rect (caca_canvas_t * cv, int x, int y, int
       width, int height)

Add an invalidating zone to the canvas's dirty rectangle list. For more information about the dirty rectangles, see caca_get_dirty_rect().

This function may be useful to force refresh of a given zone of the canvas even if the dirty rectangle tracking indicates that it is unchanged. This may happen if the canvas contents were somewhat directly modified. 🙈

If an error occurs, -1 is returned and errno is set accordingly:

• EINVAL — Specified rectangle coordinates are out of bounds.

Parameters

• cv — A libcaca canvas.
• x — The leftmost edge of the additional dirty rectangle.
• y — The topmost edge of the additional dirty rectangle.
• width — The width of the additional dirty rectangle.
• height — The height of the additional dirty rectangle.

Returns

0 in case of success, -1 if an error occurred.

Referenced by caca_blit(), caca_clear_canvas(), caca_fill_box(), caca_flip(), caca_flop(), caca_free_frame(), caca_invert(), caca_put_attr(), caca_put_char(), caca_rotate_180(), caca_rotate_left(), caca_rotate_right(), caca_set_canvas_boundaries(), caca_set_frame(), caca_stretch_left(), and caca_stretch_right().

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🧚 caca_remove_dirty_rect

__extern int caca_remove_dirty_rect (caca_canvas_t * cv, int x, int y, int
       width, int height)

Mark a cell area in the canvas as not dirty. For more information about the dirty rectangles, see caca_get_dirty_rect().

Values such that xmin > xmax or ymin > ymax indicate that the dirty rectangle is empty. They will be silently ignored.

If an error occurs, -1 is returned and errno is set accordingly:

• EINVAL — Specified rectangle coordinates are out of bounds.

Parameters

• cv — A libcaca canvas.
• x — The leftmost edge of the clean rectangle.
• y — The topmost edge of the clean rectangle.
• width — The width of the clean rectangle.
• height — The height of the clean rectangle.

Returns

0 in case of success, -1 if an error occurred.

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🍓 caca_clear_dirty_rect_list

__extern int caca_clear_dirty_rect_list (caca_canvas_t * cv)

Empty the canvas's dirty rectangle list. It’s giving clean slate energy. ✨

This function never fails.

Parameters

• cv — A libcaca canvas.

Returns

This function always returns 0.

Referenced by caca_refresh_display().

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👑 Author 👑

Generated automatically by Doxygen for libcaca from the source code.

Version 0.99.beta20 · Wed May 13 2026 09:45:08 — that’s the source/version and date, bestie. Mwah 💋✨