tuxpaint-pencil-sharpener/magic/src/sharpen.c
2008-07-10 20:26:38 +00:00

282 lines
7.6 KiB
C

/*
sharpen.c
Sharpen, Trace Contour and Silhouette Magic Tool Plugin
Tux Paint - A simple drawing program for children.
FIXME: Credits
Copyright (c) 2002-2008 by Bill Kendrick and others; see AUTHORS.txt
bill@newbreedsoftware.com
http://www.tuxpaint.org/
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
(See COPYING.txt)
Last updated: July 8, 2008
$Id$
*/
#include <stdio.h>
#include <string.h>
#include <libintl.h>
#include "tp_magic_api.h"
#include "SDL_image.h"
#include "SDL_mixer.h"
#include <math.h>
#include <limits.h>
#ifndef gettext_noop
#define gettext_noop(String) String
#endif
/* Our globals: */
enum {
TOOL_TRACE,
TOOL_SHARPEN,
TOOL_SILHOUETTE,
sharpen_NUM_TOOLS
};
//Holder for the unnormalised edge values
double* sharpen_temp;
const int THRESHOLD = 50;
const double SHARPEN = 0.5;
static Mix_Chunk * sharpen_snd_effect[sharpen_NUM_TOOLS];
const char * sharpen_snd_filenames[sharpen_NUM_TOOLS] = {
"flip.wav",
"flip.wav",
"flip.wav"
};
const char * sharpen_icon_filenames[sharpen_NUM_TOOLS] = {
"flip.png",
"flip.png",
"flip.png"
};
const char * sharpen_names[sharpen_NUM_TOOLS] = {
gettext_noop("Trace Contour"),
gettext_noop("Sharpen"),
gettext_noop("Silhouette")
};
const char * sharpen_descs[sharpen_NUM_TOOLS] = {
gettext_noop("Click to trace the edges of objects in the image."),
gettext_noop("Click to sharpen the image."),
gettext_noop("Click to create a black and white silhouette of the image.")
};
Uint32 sharpen_api_version(void) { return(TP_MAGIC_API_VERSION); }
// No setup required:
int sharpen_init(magic_api * api){
int i;
char fname[1024];
for (i = 0; i < sharpen_NUM_TOOLS; i++){
snprintf(fname, sizeof(fname), "%s/sounds/magic/%s", api->data_directory, sharpen_snd_filenames[i]);
sharpen_snd_effect[i] = Mix_LoadWAV(fname);
}
return(1);
}
// We have multiple tools:
int sharpen_get_tool_count(magic_api * api)
{
return(sharpen_NUM_TOOLS);
}
// Load our icons:
SDL_Surface * sharpen_get_icon(magic_api * api, int which){
char fname[1024];
snprintf(fname, sizeof(fname), "%simages/magic/%s", api->data_directory, sharpen_icon_filenames[which]);
return(IMG_Load(fname));
}
// Return our names, localized:
char * sharpen_get_name(magic_api * api, int which){
return(strdup(gettext(sharpen_names[which])));
}
// Return our descriptions, localized:
char * sharpen_get_description(magic_api * api, int which, int mode){
return(strdup(gettext(sharpen_descs[which])));
}
//Calculates the grey scale value for a rgb pixel
static int sharpen_grey(Uint8 r1,Uint8 g1,Uint8 b1){
return 0.3*r1+.59*g1+0.11*b1;
}
// Do the effect:
static void do_sharpen(void * ptr,SDL_Surface * canvas, SDL_Surface * last, int which)
{
magic_api * api = (magic_api *) ptr;
sharpen_temp = (double*)malloc(api->canvas_w*api->canvas_h*sizeof(double));
int x, y;
int grey;
Uint8 r1, g1, b1;
//For sobel calculation
int i,j;
int sobel_1,sobel_2;
//For normalisation
double min=INT_MAX;
double max=0;
//Sobel weighting masks
const int sobel_weights_1[3][3] = { {1,2,1},
{0,0,0},
{-1,-2,-1}};
const int sobel_weights_2[3][3] = { {-1,0,1},
{-2,0,2},
{-1,0,1}};
for (y = 0; y < canvas->h; y++){
for (x=0; x < canvas->w; x++){
//Calculate Sobel edge values
sobel_1=0;
sobel_2=0;
for (i=-1;i<2;i++){
for(j=-1; j<2; j++){
//No need to check if inside canvas, getpixel does it for us.
SDL_GetRGB(api->getpixel(last, x+i, y+j), last->format, &r1, &g1, &b1);
grey = sharpen_grey(r1,g1,b1);
sobel_1 += grey * sobel_weights_1[i+1][j+1];
sobel_2 += grey * sobel_weights_2[i+1][j+1];
}
}
//And store in temp variable
//Cant just write to surface as they may not be 0-255 and surface will clamp them and lose data
sharpen_temp[x*(canvas->h-1) + y] = sqrt(sobel_1*sobel_1 + sobel_2*sobel_2);
//Calculate normalisation
if (sharpen_temp[x*(canvas->h-1) + y]<min){
min=sharpen_temp[x*(canvas->h-1) + y];
}
if(sharpen_temp[x*(canvas->h-1) + y]>max){
max=sharpen_temp[x*(canvas->h-1) + y];
}
}
}
for (y = 0; y < canvas->h; y++){
for (x=0; x < canvas->w; x++){
//apply normalisation
sharpen_temp[x*(canvas->h-1) + y]= ((sharpen_temp[x*(canvas->h-1) + y]-min)/(max-min))*255.0;
// set image to white where edge value is below THRESHOLD
if (which == TOOL_TRACE){
if (sharpen_temp[x*(canvas->h-1) + y]<THRESHOLD)
{
api->putpixel(canvas, x, y, SDL_MapRGB(canvas->format, 255, 255, 255));
}
}
//Simply display the edge values - provides a nice black and white silhouette image
else if (which == TOOL_SILHOUETTE){
api->putpixel(canvas, x, y, SDL_MapRGB(canvas->format, sharpen_temp[x*(canvas->h-1) + y],
sharpen_temp[x*(canvas->h-1) + y],
sharpen_temp[x*(canvas->h-1) + y]));
}
//Add the edge values to the original image, creating a more distinct jump in contrast at edges
else if(which == TOOL_SHARPEN){
SDL_GetRGB(api->getpixel(last, x, y), last->format, &r1, &g1, &b1);
api->putpixel(canvas, x, y, SDL_MapRGB(canvas->format, clamp(0.0, r1 + SHARPEN * sharpen_temp[x*(canvas->h-1) + y], 255.0),
clamp(0.0, g1 + SHARPEN * sharpen_temp[x*(canvas->h-1) + y], 255.0),
clamp(0.0, b1 + SHARPEN * sharpen_temp[x*(canvas->h-1) + y], 255.0)));
}
}
}
//Clean up temp variable
if (sharpen_temp != NULL){
free(sharpen_temp);
}
}
// Affect the canvas on drag:
void sharpen_drag(magic_api * api, int which, SDL_Surface * canvas,
SDL_Surface * last, int ox, int oy, int x, int y,
SDL_Rect * update_rect)
{
// No-op
}
// Affect the canvas on click:
void sharpen_click(magic_api * api, int which, int mode,
SDL_Surface * canvas, SDL_Surface * last,
int x, int y, SDL_Rect * update_rect)
{
update_rect->x = 0;
update_rect->y = 0;
update_rect->w = canvas->w;
update_rect->h = canvas->h;
do_sharpen(api, canvas, last, which);
//play sound
api->playsound(sharpen_snd_effect[which], 128, 255);
}
// Affect the canvas on release:
void sharpen_release(magic_api * api, int which,
SDL_Surface * canvas, SDL_Surface * last,
int x, int y, SDL_Rect * update_rect)
{
}
// No setup happened:
void sharpen_shutdown(magic_api * api)
{
//Clean up sounds
int i;
for(i=0; i<sharpen_NUM_TOOLS; i++){
if(sharpen_snd_effect[i] != NULL){
Mix_FreeChunk(sharpen_snd_effect[i]);
}
}
}
// Record the color from Tux Paint:
void sharpen_set_color(magic_api * api, Uint8 r, Uint8 g, Uint8 b)
{
}
// Use colors:
int sharpen_requires_colors(magic_api * api, int which)
{
return 0;
}
void sharpen_switchin(magic_api * api, int which, int mode, SDL_Surface * canvas)
{
}
void sharpen_switchout(magic_api * api, int which, int mode, SDL_Surface * canvas)
{
}
int sharpen_modes(magic_api * api, int which)
{
return(MODE_FULLSCREEN); /* FIXME - Can also be turned into a painted effect */
}