libcaca documentation

Migrating from libcaca 0.x to the 1.0 API

This section will guide you through the migration of a libcaca 0.x application to the latest API version.

# Overview

The most important change in the 1.0 API of libcaca is the object-oriented design. See these two examples for a rough idea of what changed:

#include <caca.h> /* libcaca program - 0.x API */ int main(void) { /* Initialise libcaca */ caca_init(); /* Set window title */ caca_set_window_title("Window"); /* Choose drawing colours */ caca_set_color(CACA_COLOR_BLACK, CACA_COLOR_WHITE); /* Draw a string at (0, 0) */ caca_putstr(0, 0, "Hello world!"); /* Refresh display */ caca_refresh(); /* Wait for a key press event */ caca_wait_event(CACA_EVENT_KEY_PRESS); /* Clean up library */ caca_end(); return 0; } caca.h The libcaca public header. CACA_EVENT_KEY_PRESS @ CACA_EVENT_KEY_PRESS Definition caca.h:113 | #include <caca.h> /* libcaca program - 1.0 API */ int main(void) { /* Initialise libcaca */ caca_canvas_t *cv; caca_display_t *dp; dp = caca_create_display(NULL); cv = caca_get_canvas(dp); /* Set window title */ caca_set_display_title(dp, "Window"); /* Choose drawing colours */ caca_set_color_ansi(cv, CACA_BLACK, CACA_WHITE); /* Draw a string at (0, 0) */ caca_put_str(cv, 0, 0, "Hello world!"); /* Refresh display */ caca_refresh_display(); /* Wait for a key press event */ caca_get_event(dp, CACA_EVENT_KEY_PRESS, NULL, -1); /* Clean up library */ caca_free_display(dp); return 0; } caca_canvas_t struct caca_canvas caca_canvas_t Definition caca.h:51 caca_display_t struct caca_display caca_display_t Definition caca.h:61 CACA_WHITE @ CACA_WHITE Definition caca.h:88 CACA_BLACK @ CACA_BLACK Definition caca.h:73 caca_set_color_ansi int caca_set_color_ansi(caca_canvas_t *cv, uint8_t fg, uint8_t bg) Set the default colour pair for text (ANSI version). Definition attr.c:234 caca_put_str __extern int caca_put_str(caca_canvas_t *, int, int, char const *) Print a string. Definition string.c:258 caca_create_display caca_display_t * caca_create_display(caca_canvas_t *cv) Attach a caca graphical context to a caca canvas. Definition caca/caca.c:74 caca_refresh_display __extern int caca_refresh_display(caca_display_t *) Flush pending changes and redraw the screen. Definition graphics.c:146 caca_get_canvas caca_canvas_t * caca_get_canvas(caca_display_t *dp) Get the canvas attached to a caca graphical context. Definition caca/caca.c:265 caca_free_display int caca_free_display(caca_display_t *dp) Detach a caca graphical context from a caca backend context. Definition caca/caca.c:244 caca_set_display_title __extern int caca_set_display_title(caca_display_t *, char const *) Set the display title. Definition graphics.c:40 caca_get_event __extern int caca_get_event(caca_display_t *, int, caca_event_t *, int) Get the next mouse or keyboard input event. Definition event.c:63

Note the following important things:

- Most functions now take an object handle as their first argument.

# Migration strategy

You have two ways to migrate your application to use libcaca 1.x:

- Port your code using the function equivalence list. This is the preferred way because new functions are thread safe and offer much more features to both the programmer and the end user.
- Use the legacy compatibility layer.

Using the compatibility layer is as easy as adding the following three lines:

#include <caca.h> /* libcaca program - 0.x API */ ... | #include <caca.h> #ifdef CACA_API_VERSION_1 # include <caca0.h> #endif /* libcaca program - 0.x API */ ...

The modified code is guaranteed to build both with libcaca 0.x and libcaca 1.0.

# Function equivalence list

## Basic functions

- caca_init(): use caca_create_canvas() to create a libcaca canvas, followed by caca_create_display() to attach a libcaca display to it. Alternatively, caca_create_display() with a NULL argument will create a canvas automatically.
- caca_set_delay(): use caca_set_display_time().
- caca_get_feature(): deprecated.
- caca_set_feature(): deprecated, see caca_set_dither_antialias(), caca_set_dither_color() and caca_set_dither_mode() instead.
- caca_get_feature_name(): deprecated, see caca_get_dither_mode_list(), caca_get_dither_antialias_list() and caca_get_dither_color_list() instead.
- caca_get_rendertime(): use caca_get_display_time().
- caca_get_width(): use caca_get_canvas_width().
- caca_get_height(): use caca_get_canvas_height().
- caca_set_window_title(): use caca_set_display_title().
- caca_get_window_width(): use caca_get_display_width().
- caca_get_window_height(): use caca_get_display_height().
- caca_refresh(): use caca_refresh_display().
- caca_end(): use caca_free_display() to detach the libcaca display, followed by caca_free_canvas() to free the underlying libcaca canvas. Alternatively, if the canvas was created by caca_create_display(), it will be automatically destroyed by caca_free_display().

## Event handling

- caca_get_event(): unchanged, but the event information retrieval changed a lot.
- caca_wait_event(): use caca_get_event() with a `timeout` argument of -1.
- caca_get_mouse_x(): unchanged.
- caca_get_mouse_y(): unchanged.

## Character printing

- caca_set_color(): use caca_set_color_ansi() or caca_set_color_argb().
- caca_get_fg_color(): use caca_get_attr().
- caca_get_bg_color(): use caca_get_attr().
- caca_get_color_name(): this function is now deprecated due to major uselessness.
- caca_putchar(): use caca_put_char().
- caca_putstr(): use caca_put_str().
- caca_printf(): unchanged.
- caca_clear(): use caca_clear_canvas().

## Primitives drawing

These functions are almost unchanged, except for Unicode support and the fact that they now act on a given canvas.

- caca_draw_line(): unchanged.
- caca_draw_polyline(): unchanged.
- caca_draw_thin_line(): unchanged.
- caca_draw_thin_polyline(): unchanged.
- caca_draw_circle(): unchanged.
- caca_draw_ellipse(): unchanged.
- caca_draw_thin_ellipse(): unchanged.
- caca_fill_ellipse(): unchanged.
- caca_draw_box(): unchanged, but the argument meaning changed (width and height instead of corner coordinates).
- caca_draw_thin_box(): use caca_draw_thin_box() or caca_draw_cp437_box(), also the argument meaning changed (width and height instead of corner coordinates).
- caca_fill_box(): unchanged, but the argument meaning changed (width and height instead of corner coordinates).
- caca_draw_triangle(): unchanged.
- caca_draw_thin_triangle(): unchanged.
- caca_fill_triangle(): unchanged.

## Mathematical functions

- caca_rand(): unchanged, but the second argument is different, make sure you take that into account.
- caca_sqrt(): this function is now deprecated, use your system's sqrt() call instead.

## Sprite handling

The newly introduced canvases can have several frames. Sprites are hence completely deprecated.

- caca_load_sprite(): use caca_import_file().
- caca_get_sprite_frames(): use caca_get_frame_count().
- caca_get_sprite_width(): use caca_get_canvas_width().
- caca_get_sprite_height(): use caca_get_canvas_height().
- caca_get_sprite_dx(): use caca_get_canvas_handle_x().
- caca_get_sprite_dy(): use caca_get_canvas_handle_y().
- caca_draw_sprite(): use caca_set_frame() and caca_blit().
- caca_free_sprite(): use caca_free_canvas().

## Bitmap handling

Bitmaps have been renamed to dithers, because these objects do not in fact store any pixels, they just have information on how bitmaps will be dithered.

- caca_create_bitmap(): use caca_create_dither().
- caca_set_bitmap_palette(): use caca_set_dither_palette().
- caca_draw_bitmap(): use caca_dither_bitmap().
- caca_free_bitmap(): use caca_free_dither().

# Compilation

The `caca-config` utility is deprecated in favour of the standard `pkg-config` interface:

gcc -c foobar.c -o foobar.o `pkg-config --cflags caca`
gcc foobar.o -o foobar `pkg-config --libs caca`

`caca-config` is still provided as a convenience tool but may be removed in the future.