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"xorpixel()" function added to Magic Tools API

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This commit is contained in:
Bill Kendrick 2021-02-20 15:19:40 -08:00
parent d588e5d214
commit 7cd547e746
6 changed files with 103 additions and 62 deletions
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6
Makefile
View file

@ -1,10 +1,10 @@
# Tux Paint - A simple drawing program for children.
# Copyright (c) 2002-2020
# Copyright (c) 2002-2021
# Various contributors (see AUTHORS.txt)
# http://www.tuxpaint.org/
# June 14, 2002 - December 27, 2020
# June 14, 2002 - January 2, 2020
# The version number, for release:
@ -15,7 +15,7 @@ ifdef SOURCE_DATE_EPOCH
else
VER_DATE=$(shell date "+%Y-%m-%d")
endif
MAGIC_API_VERSION:=0x00000003
MAGIC_API_VERSION:=0x00000004
# Need to know the OS

2
docs/CHANGES.txt
View file

@ -19,6 +19,8 @@ $Id$
(Use the "colorsrows" option.)
Pere Pujal i Carabantes <pere@fornol.no-ip.org>
* A new "xorpixel()" function has been added to the Magic Tools API.
* New Magic Tools:
----------------
* Checkerboard

21
magic/docs/en/README.txt
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@ -3,7 +3,7 @@
Copyright 2007-2018 by various contributors; see AUTHORS.txt
http://www.tuxpaint.org/
July 5, 2007 - August 30, 2018
July 5, 2007 - February 20, 2021
----------------------------------------------------------------------
@ -392,6 +392,13 @@ Interfaces
RGB values to a Uint32 'pixel' value appropriate to the
destination surface.)
* Uint32 xorpixel(SDL_Surface * surf, int x, int y)
Applies an XOR (exclusive-or) operation to the pixel at
coordinates (x,y) of the SDL_Surface. Applying an XOR again at
the same position will return the pixel to the original value.
Useful for displaying temporary 'rubberband' lines, outlines,
and crosshairs, while utilizing a Magic Tool.
* SDL_Surface * scale(SDL_Surface * surf, int w, int h,
int keep_aspect)
This accepts an existing SDL surface and creates a new one
@ -648,12 +655,12 @@ Compiling
A snippet from a Makefile to compile a Tux Paint "Magic" tool plugin
might look like this:
+----------------------------------------------------------------+
+------------------------------------------------------+
| CFLAGS=-Wall -O2 $(shell tp-magic-config --cflags) |
| |
| my_plugin.so: my_plugin.c |
| gcc -shared $(CFLAGS) -o my_plugin.so my_plugin.c |
+----------------------------------------------------------------+
+------------------------------------------------------+
The first line sets up Makefile variable ("CFLAGS") that contains
flags for the compiler. "-Wall" asks for all compiler warnings to be
@ -683,7 +690,7 @@ Compiling
An even more generalized Makefile might look like this:
+----------------------------------------------------------------+
+----------------------------------------------------+
| CFLAGS=-Wall -O2 $(shell tp-magic-config --cflags) |
| |
| my_plugin_1.so: my_plugin_1.c |
@ -691,7 +698,7 @@ Compiling
| |
| my_plugin_2.so: my_plugin_2.c |
| $(CC) -shared $(CFLAGS) -o $@ $< |
+----------------------------------------------------------------+
+----------------------------------------------------+
As before, there are lines that define the command "make" should run
when it determines that it needs to (re)compile the ".so" file(s).
@ -799,7 +806,7 @@ Installing
A snippet from a more generalized Makefile might look like this:
+----------------------------------------------------------------+
+------------------------------------------------------------+
| PLUGINPREFIX=$(shell tp-magic-config --pluginprefix) |
| PLUGINDOCPREFIX=$(shell tp-magic-config --plugindocprefix) |
| DATAPREFIX=$(shell tp-magic-config --dataprefix) |
@ -827,7 +834,7 @@ Installing
| cp docs/*.txt $(PLUGINDOCPREFIX)/ |
| chmod 644 $(PLUGINDOCPREFIX)/html/*.html |
| chmod 644 $(PLUGINDOCPREFIX)/*.txt |
+----------------------------------------------------------------+
+------------------------------------------------------------+
The first three lines set up Makefile variables that contain the
paths returned by the "tp-magic-config" command-line tool. (The

11
magic/docs/en/html/README.html
View file

@ -12,7 +12,7 @@ alink="#FF00FF">
<p>Copyright 2007-2018 by various contributors; see AUTHORS.txt<br/>
<a href="http://www.tuxpaint.org/">http://www.tuxpaint.org/</a></p>
<p>July 5, 2007 - August 30, 2018</p>
<p>July 5, 2007 - February 20, 2021</p>
</center>
<hr size=2 noshade>
@ -497,6 +497,15 @@ plugin's functions.
surface.)<br>
<br>
<li><code><b>Uint32 xorpixel(SDL_Surface&nbsp;*&nbsp;surf,
int&nbsp;x, int&nbsp;y)</b></code><br>
Applies an XOR (exclusive-or) operation to the pixel at coordinates
(x,y) of the SDL_Surface. Applying an XOR again at the same position
will return the pixel to the original value. Useful for displaying
temporary 'rubberband' lines, outlines, and crosshairs, while
utilizing a Magic Tool.<br>
<br>
<li><code><b>SDL_Surface * scale(SDL_Surface&nbsp;*&nbsp;surf,
int&nbsp;w, int&nbsp;h, int&nbsp;keep_aspect)</b></code><br>
This accepts an existing SDL surface and creates a new one scaled to an

3
src/tp_magic_api.h.in
View file

@ -110,6 +110,9 @@ typedef struct magic_api_t {
SDL_MustLockSurface() can tell you whether a surface needs to be locked. */
void (*putpixel)(SDL_Surface *, int, int, Uint32);
/* XOR's the pixel at (x,y) location of the surface. */
Uint32 (*xorpixel)(SDL_Surface *, int, int);
/* Asks Tux Paint to play a sound (one loaded via SDL_mixer library);
the first value is for left/right panning (0 is left, 128 is center,
255 is right); the second value is for total volume (0 is off, 255 is

46
src/tuxpaint.c
View file

@ -22,7 +22,7 @@
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
(See COPYING.txt)
June 14, 2002 - January 26, 2021
June 14, 2002 - February 20, 2021
*/
@ -751,6 +751,7 @@ static int WINDOW_HEIGHT = 600;
static void magic_putpixel(SDL_Surface * surface, int x, int y, Uint32 pixel);
static Uint32 magic_getpixel(SDL_Surface * surface, int x, int y);
static void magic_xorpixel(SDL_Surface * surface, int x, int y);
/**
* Sets a variety of screen layout globals, based on the
@ -1915,6 +1916,7 @@ static void draw_none(void);
static void do_undo(void);
static void do_redo(void);
static void render_brush(void);
static void _xorpixel(SDL_Surface * surf, int x, int y);
static void line_xor(int x1, int y1, int x2, int y2);
static void rect_xor(int x1, int y1, int x2, int y2);
static void draw_blinking_cursor(void);
@ -9920,32 +9922,26 @@ static SDL_Surface *zoom(SDL_Surface * src, int new_w, int new_h)
#endif
/**
* FIXME
*/
/* XOR must show up on black, white, 0x7f grey, and 0x80 grey.
XOR must be exactly 100% perfectly reversable. */
static void xorpixel(int x, int y)
static void _xorpixel(SDL_Surface * surf, int x, int y)
{
Uint8 *p;
int BytesPerPixel;
/* if outside the canvas, return */
if ((unsigned)x >= (unsigned)canvas->w || (unsigned)y >= (unsigned)canvas->h)
if (x < 0 || x >= surf->w || y < 0 || y >= surf->h)
return;
/* now switch to screen coordinates */
x += r_canvas.x;
y += r_canvas.y;
/* Always 4, except 3 when loading a saved image. */
BytesPerPixel = screen->format->BytesPerPixel;
BytesPerPixel = surf->format->BytesPerPixel;
/* Set a pointer to the exact location in memory of the pixel */
p = (Uint8 *) (((Uint8 *) screen->pixels) + /* Start: beginning of RAM */
(y * screen->pitch) + /* Go down Y lines */
p = (Uint8 *) (((Uint8 *) surf->pixels) + /* Start: beginning of RAM */
(y * surf->pitch) + /* Go down Y lines */
(x * BytesPerPixel)); /* Go in X pixels */
/* XOR the (correctly-sized) piece of data in the screen's RAM */
/* XOR the (correctly-sized) piece of data in the surface's RAM */
if (likely(BytesPerPixel == 4))
*(Uint32 *) p ^= 0x80808080u; /* 32-bit display */
else if (BytesPerPixel == 1)
@ -9960,6 +9956,21 @@ static void xorpixel(int x, int y)
}
}
/**
* FIXME
*/
static void xorpixel(int x, int y) {
/* if outside the canvas, return */
if ((unsigned)x >= (unsigned)canvas->w || (unsigned)y >= (unsigned)canvas->h)
return;
/* now switch to screen coordinates */
x += r_canvas.x;
y += r_canvas.y;
_xorpixel(screen, x, y);
}
/**
* FIXME
@ -18655,6 +18666,7 @@ static void load_magic_plugins(void)
magic_api_struct->in_circle = in_circle_rad;
magic_api_struct->getpixel = magic_getpixel;
magic_api_struct->putpixel = magic_putpixel;
magic_api_struct->xorpixel = magic_xorpixel;
magic_api_struct->line = magic_line_func;
magic_api_struct->playsound = magic_playsound;
magic_api_struct->stopsound = magic_stopsound;
@ -21301,6 +21313,14 @@ static Uint32 magic_getpixel(SDL_Surface * surface, int x, int y)
return (getpixels[surface->format->BytesPerPixel] (surface, x, y));
}
/**
* FIXME
*/
static void magic_xorpixel(SDL_Surface * surface, int x, int y)
{
_xorpixel(surface, x, y);
}
/**
* FIXME