hackthelobby/libcaca/caca/canvas.c

536 lines
15 KiB
C

/*
* libcaca Colour ASCII-Art library
* Copyright © 2002—2021 Sam Hocevar <sam@hocevar.net>
* All Rights Reserved
*
* This library is free software. It comes without any warranty, to
* the extent permitted by applicable law. You can redistribute it
* and/or modify it under the terms of the Do What the Fuck You Want
* to Public License, Version 2, as published by Sam Hocevar. See
* http://www.wtfpl.net/ for more details.
*/
/*
* This file contains the main functions used by \e libcaca applications
* to initialise a drawing context.
*/
#include "config.h"
#if !defined(__KERNEL__)
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
# include <time.h>
# include <sys/types.h>
# if defined(HAVE_UNISTD_H)
# include <unistd.h>
# endif
#endif
#include "caca.h"
#include "caca_internals.h"
static int caca_resize(caca_canvas_t *, int, int);
/** \brief Initialise a \e libcaca canvas.
*
* Initialise internal \e libcaca structures and the backend that will
* be used for subsequent graphical operations. It must be the first
* \e libcaca function to be called in a function. caca_free_canvas()
* should be called at the end of the program to free all allocated resources.
*
* Both the cursor and the canvas' handle are initialised at the top-left
* corner.
*
* If an error occurs, NULL is returned and \b errno is set accordingly:
* - \c EINVAL Specified width or height is invalid.
* - \c EOVERFLOW Specified width and height overflowed.
* - \c ENOMEM Not enough memory for the requested canvas size.
*
* \param width The desired canvas width
* \param height The desired canvas height
* \return A libcaca canvas handle upon success, NULL if an error occurred.
*/
caca_canvas_t * caca_create_canvas(int width, int height)
{
caca_canvas_t *cv;
if(width < 0 || height < 0)
{
seterrno(EINVAL);
return NULL;
}
cv = malloc(sizeof(caca_canvas_t));
if(!cv)
goto nomem;
cv->refcount = 0;
cv->autoinc = 0;
cv->resize_callback = NULL;
cv->resize_data = NULL;
cv->frame = 0;
cv->framecount = 1;
cv->frames = malloc(sizeof(struct caca_frame));
if(!cv->frames)
{
free(cv);
goto nomem;
}
cv->frames[0].width = cv->frames[0].height = 0;
cv->frames[0].chars = NULL;
cv->frames[0].attrs = NULL;
cv->frames[0].x = cv->frames[0].y = 0;
cv->frames[0].handlex = cv->frames[0].handley = 0;
cv->frames[0].curattr = 0;
cv->frames[0].name = strdup("frame#00000000");
_caca_load_frame_info(cv);
caca_set_color_ansi(cv, CACA_DEFAULT, CACA_TRANSPARENT);
cv->ndirty = 0;
cv->dirty_disabled = 0;
cv->ff = NULL;
if(caca_resize(cv, width, height) < 0)
{
int saved_errno = geterrno();
free(cv->frames[0].name);
free(cv->frames);
free(cv);
seterrno(saved_errno);
return NULL;
}
return cv;
nomem:
seterrno(ENOMEM);
return NULL;
}
/** \brief Manage a canvas.
*
* Lock a canvas to prevent it from being resized. If non-NULL,
* the \e callback function pointer will be called upon each
* \e caca_set_canvas_size call and if the returned value is zero, the
* canvas resize request will be denied.
*
* This function is only useful for display drivers such as the \e libcaca
* library.
*
* If an error occurs, -1 is returned and \b errno is set accordingly:
* - \c EBUSY The canvas is already being managed.
*
* \param cv A libcaca canvas.
* \param callback An optional callback function pointer.
* \param p The argument to be passed to \e callback.
* \return 0 in case of success, -1 if an error occurred.
*/
int caca_manage_canvas(caca_canvas_t *cv, int (*callback)(void *), void *p)
{
if(cv->refcount)
{
seterrno(EBUSY);
return -1;
}
cv->resize_callback = callback;
cv->resize_data = p;
cv->refcount = 1;
return 0;
}
/** \brief unmanage a canvas.
*
* unlock a canvas previously locked by caca_manage_canvas(). for safety
* reasons, the callback and callback data arguments must be the same as for
* the caca_manage_canvas() call.
*
* this function is only useful for display drivers such as the \e libcaca
* library.
*
* if an error occurs, -1 is returned and \b errno is set accordingly:
* - \c einval the canvas is not managed, or the callback arguments do
* not match.
*
* \param cv a libcaca canvas.
* \param callback the \e callback argument previously passed to
* caca_manage_canvas().
* \param p the \e p argument previously passed to caca_manage_canvas().
* \return 0 in case of success, -1 if an error occurred.
*/
int caca_unmanage_canvas(caca_canvas_t *cv, int (*callback)(void *), void *p)
{
if(!cv->refcount
|| cv->resize_callback != callback || cv->resize_data != p)
{
seterrno(EINVAL);
return -1;
}
cv->refcount = 0;
return 0;
}
/** \brief Resize a canvas.
*
* Set the canvas' width and height, in character cells.
*
* The contents of the canvas are preserved to the extent of the new
* canvas size. Newly allocated character cells at the right and/or at
* the bottom of the canvas are filled with spaces.
*
* If as a result of the resize the cursor coordinates fall outside the
* new canvas boundaries, they are readjusted. For instance, if the
* current X cursor coordinate is 11 and the requested width is 10, the
* new X cursor coordinate will be 10.
*
* It is an error to try to resize the canvas if an output driver has
* been attached to the canvas using caca_create_display(). You need to
* remove the output driver using caca_free_display() before you can change
* the canvas size again. However, the caca output driver can cause a
* canvas resize through user interaction. See the caca_event() documentation
* for more about this.
*
* If an error occurs, -1 is returned and \b errno is set accordingly:
* - \c EINVAL Specified width or height is invalid.
* - \c EOVERFLOW Specified width and height overflowed.
* - \c EBUSY The canvas is in use by a display driver and cannot be resized.
* - \c ENOMEM Not enough memory for the requested canvas size. If this
* happens, the canvas handle becomes invalid and should not be used.
*
* \param cv A libcaca canvas.
* \param width The desired canvas width.
* \param height The desired canvas height.
* \return 0 in case of success, -1 if an error occurred.
*/
int caca_set_canvas_size(caca_canvas_t *cv, int width, int height)
{
if(width < 0 || height < 0)
{
seterrno(EINVAL);
return -1;
}
if(cv->refcount && cv->resize_callback
&& !cv->resize_callback(cv->resize_data))
{
seterrno(EBUSY);
return -1;
}
return caca_resize(cv, width, height);
}
/** \brief Get the canvas width.
*
* Return the current canvas' width, in character cells.
*
* This function never fails.
*
* \param cv A libcaca canvas.
* \return The canvas width.
*/
int caca_get_canvas_width(caca_canvas_t const *cv)
{
return cv->width;
}
/** \brief Get the canvas height.
*
* Returns the current canvas' height, in character cells.
*
* This function never fails.
*
* \param cv A libcaca canvas.
* \return The canvas height.
*/
int caca_get_canvas_height(caca_canvas_t const *cv)
{
return cv->height;
}
/** \brief Get the canvas character array.
*
* Return the current canvas' internal character array. The array elements
* consist in native endian 32-bit Unicode values as returned by
* caca_get_char().
*
* This function is probably only useful for \e libcaca 's internal display
* drivers.
*
* This function never fails.
*
* \param cv A libcaca canvas.
* \return The canvas character array.
*/
uint32_t const * caca_get_canvas_chars(caca_canvas_t const *cv)
{
return (uint32_t const *)cv->chars;
}
/** \brief Get the canvas attribute array.
*
* Returns the current canvas' internal attribute array. The array elements
* consist in native endian 32-bit attribute values as returned by
* caca_get_attr().
*
* This function is probably only useful for \e libcaca 's internal display
* drivers.
*
* This function never fails.
*
* \param cv A libcaca canvas.
* \return The canvas attribute array.
*/
uint32_t const * caca_get_canvas_attrs(caca_canvas_t const *cv)
{
return (uint32_t const *)cv->attrs;
}
/** \brief Free a \e libcaca canvas.
*
* Free all resources allocated by caca_create_canvas(). The canvas
* pointer becomes invalid and must no longer be used unless a new call
* to caca_create_canvas() is made.
*
* If an error occurs, -1 is returned and \b errno is set accordingly:
* - \c EBUSY The canvas is in use by a display driver and cannot be freed.
*
* \param cv A libcaca canvas.
* \return 0 in case of success, -1 if an error occurred.
*/
int caca_free_canvas(caca_canvas_t *cv)
{
int f;
if(cv->refcount)
{
seterrno(EBUSY);
return -1;
}
for(f = 0; f < cv->framecount; f++)
{
free(cv->frames[f].chars);
free(cv->frames[f].attrs);
free(cv->frames[f].name);
}
caca_canvas_set_figfont(cv, NULL);
free(cv->frames);
free(cv);
return 0;
}
/** \brief Generate a random integer within a range.
*
* Generate a random integer within the given range.
*
* This function never fails.
*
* \param min The lower bound of the integer range.
* \param max The upper bound of the integer range.
* \return A random integer comprised between \p min and \p max - 1
* (inclusive).
*/
static caca_timer_t timer = {0, 0};
int caca_rand(int min, int max)
{
static int need_init = 1;
if(need_init)
{
srand(getpid() + _caca_getticks(&timer));
need_init = 0;
}
return min + (int)((1.0 * (max - min)) * rand() / (RAND_MAX + 1.0));
}
/*
* XXX: The following functions are local.
*/
int caca_resize(caca_canvas_t *cv, int width, int height)
{
int x, y, f, old_width, old_height, old_size;
/* Check for overflow */
int new_size = width * height;
if (new_size < 0 || (width > 0 && new_size / width != height))
{
seterrno(EOVERFLOW);
return -1;
}
old_width = cv->width;
old_height = cv->height;
old_size = old_width * old_height;
_caca_save_frame_info(cv);
/* Preload new width and height values into the canvas to optimise
* dirty rectangle handling */
cv->width = width;
cv->height = height;
/* If width or height is smaller (or both), we have the opportunity to
* reduce or even remove dirty rectangles */
if(width < old_width || height < old_height)
_caca_clip_dirty_rect_list(cv);
/* Step 1: if new area is bigger, resize the memory area now. */
if(new_size > old_size)
{
for(f = 0; f < cv->framecount; f++)
{
cv->frames[f].chars = realloc(cv->frames[f].chars,
new_size * sizeof(uint32_t));
cv->frames[f].attrs = realloc(cv->frames[f].attrs,
new_size * sizeof(uint32_t));
if(new_size && (!cv->frames[f].chars || !cv->frames[f].attrs))
{
seterrno(ENOMEM);
return -1;
}
}
}
/* Step 2: move line data if necessary. */
if(width == old_width)
{
/* Width did not change, which means we do not need to move data. */
;
}
else if(width > old_width)
{
/* New width is bigger than old width, which means we need to
* copy lines starting from the bottom of the screen otherwise
* we will overwrite information. */
for(f = 0; f < cv->framecount; f++)
{
uint32_t *chars = cv->frames[f].chars;
uint32_t *attrs = cv->frames[f].attrs;
for(y = height < old_height ? height : old_height; y--; )
{
uint32_t attr = cv->frames[f].curattr;
for(x = old_width; x--; )
{
chars[y * width + x] = chars[y * old_width + x];
attrs[y * width + x] = attrs[y * old_width + x];
}
/* Zero the end of the line */
for(x = width - old_width; x--; )
{
chars[y * width + old_width + x] = (uint32_t)' ';
attrs[y * width + old_width + x] = attr;
}
}
}
if(!cv->dirty_disabled)
caca_add_dirty_rect(cv, old_width, 0,
width - old_width, old_height);
}
else
{
/* New width is smaller. Copy as many lines as possible. Ignore
* the first line, it is already in place. */
int lines = height < old_height ? height : old_height;
for(f = 0; f < cv->framecount; f++)
{
uint32_t *chars = cv->frames[f].chars;
uint32_t *attrs = cv->frames[f].attrs;
for(y = 1; y < lines; y++)
{
for(x = 0; x < width; x++)
{
chars[y * width + x] = chars[y * old_width + x];
attrs[y * width + x] = attrs[y * old_width + x];
}
}
}
}
/* Step 3: fill the bottom of the new screen if necessary. */
if(height > old_height)
{
for(f = 0; f < cv->framecount; f++)
{
uint32_t *chars = cv->frames[f].chars;
uint32_t *attrs = cv->frames[f].attrs;
uint32_t attr = cv->frames[f].curattr;
/* Zero the bottom of the screen */
for(x = (height - old_height) * width; x--; )
{
chars[old_height * width + x] = (uint32_t)' ';
attrs[old_height * width + x] = attr;
}
}
if(!cv->dirty_disabled)
caca_add_dirty_rect(cv, 0, old_height,
old_width, height - old_height);
}
/* If both width and height are larger, there is a new dirty rectangle
* that needs to be created in the lower right corner. */
if(!cv->dirty_disabled &&
width > old_width && height > old_height)
caca_add_dirty_rect(cv, old_width, old_height,
width - old_width, height - old_height);
/* Step 4: if new area is smaller, resize memory area now. */
if(new_size < old_size)
{
for(f = 0; f < cv->framecount; f++)
{
cv->frames[f].chars = realloc(cv->frames[f].chars,
new_size * sizeof(uint32_t));
cv->frames[f].attrs = realloc(cv->frames[f].attrs,
new_size * sizeof(uint32_t));
if(new_size && (!cv->frames[f].chars || !cv->frames[f].attrs))
{
seterrno(ENOMEM);
return -1;
}
}
}
/* Set new size */
for(f = 0; f < cv->framecount; f++)
{
if(cv->frames[f].x > (int)width)
cv->frames[f].x = width;
if(cv->frames[f].y > (int)height)
cv->frames[f].y = height;
cv->frames[f].width = width;
cv->frames[f].height = height;
}
/* Reset the current frame shortcuts */
_caca_load_frame_info(cv);
return 0;
}