mirror of
https://github.com/gryf/wmaker.git
synced 2025-12-19 04:20:27 +01:00
144 lines
2.9 KiB
C
144 lines
2.9 KiB
C
/* scale.c - image scaling
|
|
*
|
|
* Raster graphics library
|
|
*
|
|
* Copyright (c) 1997 Alfredo K. Kojima
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2 of the License, or (at your option) any later version.
|
|
*
|
|
* This library 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
|
|
* Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, write to the Free
|
|
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#include <config.h>
|
|
|
|
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <X11/Xlib.h>
|
|
|
|
#include <assert.h>
|
|
|
|
#include "wraster.h"
|
|
|
|
|
|
/*
|
|
*----------------------------------------------------------------------
|
|
* RScaleImage--
|
|
* Creates a scaled copy of an image.
|
|
*
|
|
* Returns:
|
|
* The new scaled image.
|
|
*
|
|
*----------------------------------------------------------------------
|
|
*/
|
|
RImage*
|
|
RScaleImage(RImage *image, unsigned new_width, unsigned new_height)
|
|
{
|
|
int ox;
|
|
int px, py;
|
|
register int x, y, t;
|
|
int dx, dy;
|
|
unsigned char *sr, *sg, *sb, *sa;
|
|
unsigned char *dr, *dg, *db, *da;
|
|
RImage *img;
|
|
|
|
assert(new_width >= 0 && new_height >= 0);
|
|
|
|
if (new_width == image->width && new_height == image->height)
|
|
return RCloneImage(image);
|
|
|
|
img = RCreateImage(new_width, new_height, image->data[3]!=NULL);
|
|
|
|
if (!img)
|
|
return NULL;
|
|
|
|
/* fixed point math idea taken from Imlib by
|
|
* Carsten Haitzler (Rasterman) */
|
|
dx = (image->width<<16)/new_width;
|
|
dy = (image->height<<16)/new_height;
|
|
|
|
py = 0;
|
|
|
|
dr = img->data[0];
|
|
dg = img->data[1];
|
|
db = img->data[2];
|
|
da = img->data[3];
|
|
|
|
if (image->data[3]!=NULL) {
|
|
int ot;
|
|
ot = -1;
|
|
for (y=0; y<new_height; y++) {
|
|
t = image->width*(py>>16);
|
|
|
|
sr = image->data[0]+t;
|
|
sg = image->data[1]+t;
|
|
sb = image->data[2]+t;
|
|
sa = image->data[3]+t;
|
|
|
|
ot = t;
|
|
ox = 0;
|
|
px = 0;
|
|
for (x=0; x<new_width; x++) {
|
|
px += dx;
|
|
|
|
*(dr++) = *sr;
|
|
*(dg++) = *sg;
|
|
*(db++) = *sb;
|
|
*(da++) = *sa;
|
|
|
|
t = (px - ox)>>16;
|
|
ox += t<<16;
|
|
|
|
sr += t;
|
|
sg += t;
|
|
sb += t;
|
|
sa += t;
|
|
}
|
|
py += dy;
|
|
}
|
|
} else {
|
|
int ot;
|
|
ot = -1;
|
|
for (y=0; y<new_height; y++) {
|
|
t = image->width*(py>>16);
|
|
|
|
sr = image->data[0]+t;
|
|
sg = image->data[1]+t;
|
|
sb = image->data[2]+t;
|
|
|
|
ot = t;
|
|
ox = 0;
|
|
px = 0;
|
|
for (x=0; x<new_width; x++) {
|
|
px += dx;
|
|
|
|
*(dr++) = *sr;
|
|
*(dg++) = *sg;
|
|
*(db++) = *sb;
|
|
|
|
t = (px-ox)>>16;
|
|
ox += t<<16;
|
|
|
|
sr += t;
|
|
sg += t;
|
|
sb += t;
|
|
}
|
|
py += dy;
|
|
}
|
|
}
|
|
|
|
return img;
|
|
}
|
|
|