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wmaker/wrlib/scale.c
Christophe CURIS ba8cd2abe4 Handle NULL pointer as good as possible (Coverity #50099)
As pointed by Coverity, in the "Configuration" panel of WPrefs there are
some images loaded, but if the images cannot be loaded correctly then the
returned NULL pointer can crash the application as it is dereferenced in
further function calls.

To solve this case, this patch is adding a NULL pointer check in the
functions RScaleImage (wrlib) and WMCreatePixmapFromRImage (WINGs), so both
can accept that NULL pointer to also return NULL, which means the existing
check for "icon == NULL" in the WPrefs code will be useful.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>
2015-04-25 07:53:06 -04:00

498 lines
11 KiB
C

/* scale.c - image scaling
*
* Raster graphics library
*
* Copyright (c) 1997-2003 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., 51 Franklin St, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <config.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <X11/Xlib.h>
#include <math.h>
#include <assert.h>
#include "wraster.h"
#include "scale.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 *s;
unsigned char *d;
RImage *img;
if (image == NULL)
return NULL;
if (new_width == image->width && new_height == image->height)
return RCloneImage(image);
img = RCreateImage(new_width, new_height, image->format == RRGBAFormat);
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;
d = img->data;
if (image->format == RRGBAFormat) {
for (y = 0; y < new_height; y++) {
t = image->width * (py >> 16);
s = image->data + (t << 2); /* image->data+t*4 */
ox = 0;
px = 0;
for (x = 0; x < new_width; x++) {
px += dx;
*(d++) = *(s);
*(d++) = *(s + 1);
*(d++) = *(s + 2);
*(d++) = *(s + 3);
t = (px - ox) >> 16;
ox += t << 16;
s += t << 2; /* t*4 */
}
py += dy;
}
} else {
for (y = 0; y < new_height; y++) {
t = image->width * (py >> 16);
s = image->data + (t << 1) + t; /* image->data+t*3 */
ox = 0;
px = 0;
for (x = 0; x < new_width; x++) {
px += dx;
*(d++) = *(s);
*(d++) = *(s + 1);
*(d++) = *(s + 2);
t = (px - ox) >> 16;
ox += t << 16;
s += (t << 1) + t; /* t*3 */
}
py += dy;
}
}
return img;
}
/*
* Filtered Image Rescaling code copy/pasted from
* Graphics Gems III
* Public Domain 1991 by Dale Schumacher
*/
/*
* filter function definitions
*/
#define box_support (0.5)
static double box_filter(double t)
{
if ((t > -0.5) && (t <= 0.5))
return (1.0);
return (0.0);
}
#define triangle_support (1.0)
static double triangle_filter(double t)
{
if (t < 0.0)
t = -t;
if (t < 1.0)
return (1.0 - t);
return (0.0);
}
#define bell_support (1.5)
static double bell_filter(double t) /* box (*) box (*) box */
{
if (t < 0)
t = -t;
if (t < .5)
return (.75 - (t * t));
if (t < 1.5) {
t = (t - 1.5);
return (.5 * (t * t));
}
return (0.0);
}
#define B_spline_support (2.0)
static double B_spline_filter(double t) /* box (*) box (*) box (*) box */
{
double tt;
if (t < 0)
t = -t;
if (t < 1) {
tt = t * t;
return ((.5 * tt * t) - tt + (2.0 / 3.0));
} else if (t < 2) {
t = 2 - t;
return ((1.0 / 6.0) * (t * t * t));
}
return (0.0);
}
static double sinc(double x)
{
/*
* The original code did this:
* if (x != 0) ...
* This code is unsafe, it should be:
* if (fabs(x) > EPSILON) ...
*
* But the call to fabs is already done in the *ONLY* function
* that call sinc: 'Lanczos3_filter'
*
* The goal was to avoid a Divide-by-0 error, now we also
* avoid a +/-inf result too
*/
x *= WM_PI;
if (x > 1.0E-9)
return (sin(x) / x);
return (1.0);
}
#define Lanczos3_support (3.0)
static double Lanczos3_filter(double t)
{
if (t < 0)
t = -t;
if (t < 3.0)
return (sinc(t) * sinc(t / 3.0));
return (0.0);
}
#define Mitchell_support (2.0)
#define B (1.0 / 3.0)
#define C (1.0 / 3.0)
static double Mitchell_filter(double t)
{
double tt;
tt = t * t;
if (t < 0)
t = -t;
if (t < 1.0) {
t = (((12.0 - 9.0 * B - 6.0 * C) * (t * tt))
+ ((-18.0 + 12.0 * B + 6.0 * C) * tt)
+ (6.0 - 2 * B));
return (t / 6.0);
} else if (t < 2.0) {
t = (((-1.0 * B - 6.0 * C) * (t * tt))
+ ((6.0 * B + 30.0 * C) * tt)
+ ((-12.0 * B - 48.0 * C) * t)
+ (8.0 * B + 24 * C));
return (t / 6.0);
}
return (0.0);
}
static double (*filterf)(double) = Mitchell_filter;
static double fwidth = Mitchell_support;
void wraster_change_filter(RScalingFilter type)
{
switch (type) {
case RBoxFilter:
filterf = box_filter;
fwidth = box_support;
break;
case RTriangleFilter:
filterf = triangle_filter;
fwidth = triangle_support;
break;
case RBellFilter:
filterf = bell_filter;
fwidth = bell_support;
break;
case RBSplineFilter:
filterf = B_spline_filter;
fwidth = B_spline_support;
break;
case RLanczos3Filter:
filterf = Lanczos3_filter;
fwidth = Lanczos3_support;
break;
default:
case RMitchellFilter:
filterf = Mitchell_filter;
fwidth = Mitchell_support;
break;
}
}
/*
* image rescaling routine
*/
typedef struct {
int pixel;
double weight;
} CONTRIB;
typedef struct {
int n; /* number of contributors */
CONTRIB *p; /* pointer to list of contributions */
} CLIST;
/* clamp the input to the specified range */
#define CLAMP(v,l,h) ((v)<(l) ? (l) : (v) > (h) ? (h) : v)
/* return of calloc is not checked if NULL in the function below! */
RImage *RSmoothScaleImage(RImage * src, unsigned new_width, unsigned new_height)
{
CLIST *contrib; /* array of contribution lists */
RImage *tmp; /* intermediate image */
double xscale, yscale; /* zoom scale factors */
int i, j, k; /* loop variables */
int n; /* pixel number */
double center, left, right; /* filter calculation variables */
double width, fscale; /* filter calculation variables */
double rweight, gweight, bweight;
RImage *dst;
unsigned char *p;
unsigned char *sp;
int sch = src->format == RRGBAFormat ? 4 : 3;
dst = RCreateImage(new_width, new_height, False);
/* create intermediate image to hold horizontal zoom */
tmp = RCreateImage(dst->width, src->height, False);
xscale = (double)new_width / (double)src->width;
yscale = (double)new_height / (double)src->height;
/* pre-calculate filter contributions for a row */
contrib = (CLIST *) calloc(new_width, sizeof(CLIST));
if (xscale < 1.0) {
width = fwidth / xscale;
fscale = 1.0 / xscale;
for (i = 0; i < new_width; ++i) {
contrib[i].n = 0;
contrib[i].p = (CONTRIB *) calloc((int) ceil(width * 2 + 1), sizeof(CONTRIB));
center = (double)i / xscale;
left = ceil(center - width);
right = floor(center + width);
for (j = left; j <= right; ++j) {
rweight = center - (double)j;
rweight = (*filterf) (rweight / fscale) / fscale;
if (j < 0) {
n = -j;
} else if (j >= src->width) {
n = (src->width - j) + src->width - 1;
} else {
n = j;
}
k = contrib[i].n++;
contrib[i].p[k].pixel = n * sch;
contrib[i].p[k].weight = rweight;
}
}
} else {
for (i = 0; i < new_width; ++i) {
contrib[i].n = 0;
contrib[i].p = (CONTRIB *) calloc((int) ceil(fwidth * 2 + 1), sizeof(CONTRIB));
center = (double)i / xscale;
left = ceil(center - fwidth);
right = floor(center + fwidth);
for (j = left; j <= right; ++j) {
rweight = center - (double)j;
rweight = (*filterf) (rweight);
if (j < 0) {
n = -j;
} else if (j >= src->width) {
n = (src->width - j) + src->width - 1;
} else {
n = j;
}
k = contrib[i].n++;
contrib[i].p[k].pixel = n * sch;
contrib[i].p[k].weight = rweight;
}
}
}
/* apply filter to zoom horizontally from src to tmp */
p = tmp->data;
for (k = 0; k < tmp->height; ++k) {
CONTRIB *pp;
sp = src->data + src->width * k * sch;
for (i = 0; i < tmp->width; ++i) {
rweight = gweight = bweight = 0.0;
pp = contrib[i].p;
for (j = 0; j < contrib[i].n; ++j) {
rweight += sp[pp[j].pixel] * pp[j].weight;
gweight += sp[pp[j].pixel + 1] * pp[j].weight;
bweight += sp[pp[j].pixel + 2] * pp[j].weight;
}
*p++ = CLAMP(rweight, 0, 255);
*p++ = CLAMP(gweight, 0, 255);
*p++ = CLAMP(bweight, 0, 255);
}
}
/* free the memory allocated for horizontal filter weights */
for (i = 0; i < new_width; ++i) {
free(contrib[i].p);
}
free(contrib);
/* pre-calculate filter contributions for a column */
contrib = (CLIST *) calloc(dst->height, sizeof(CLIST));
if (yscale < 1.0) {
width = fwidth / yscale;
fscale = 1.0 / yscale;
for (i = 0; i < dst->height; ++i) {
contrib[i].n = 0;
contrib[i].p = (CONTRIB *) calloc((int) ceil(width * 2 + 1), sizeof(CONTRIB));
center = (double)i / yscale;
left = ceil(center - width);
right = floor(center + width);
for (j = left; j <= right; ++j) {
rweight = center - (double)j;
rweight = (*filterf) (rweight / fscale) / fscale;
if (j < 0) {
n = -j;
} else if (j >= tmp->height) {
n = (tmp->height - j) + tmp->height - 1;
} else {
n = j;
}
k = contrib[i].n++;
contrib[i].p[k].pixel = n * 3;
contrib[i].p[k].weight = rweight;
}
}
} else {
for (i = 0; i < dst->height; ++i) {
contrib[i].n = 0;
contrib[i].p = (CONTRIB *) calloc((int) ceil(fwidth * 2 + 1), sizeof(CONTRIB));
center = (double)i / yscale;
left = ceil(center - fwidth);
right = floor(center + fwidth);
for (j = left; j <= right; ++j) {
rweight = center - (double)j;
rweight = (*filterf) (rweight);
if (j < 0) {
n = -j;
} else if (j >= tmp->height) {
n = (tmp->height - j) + tmp->height - 1;
} else {
n = j;
}
k = contrib[i].n++;
contrib[i].p[k].pixel = n * 3;
contrib[i].p[k].weight = rweight;
}
}
}
/* apply filter to zoom vertically from tmp to dst */
sp = malloc(tmp->height * 3);
for (k = 0; k < new_width; ++k) {
CONTRIB *pp;
p = dst->data + k * 3;
/* copy a column into a row */
{
int i;
unsigned char *p, *d;
d = sp;
for (i = tmp->height, p = tmp->data + k * 3; i-- > 0; p += tmp->width * 3) {
*d++ = *p;
*d++ = *(p + 1);
*d++ = *(p + 2);
}
}
for (i = 0; i < new_height; ++i) {
rweight = gweight = bweight = 0.0;
pp = contrib[i].p;
for (j = 0; j < contrib[i].n; ++j) {
rweight += sp[pp[j].pixel] * pp[j].weight;
gweight += sp[pp[j].pixel + 1] * pp[j].weight;
bweight += sp[pp[j].pixel + 2] * pp[j].weight;
}
*p = CLAMP(rweight, 0, 255);
*(p + 1) = CLAMP(gweight, 0, 255);
*(p + 2) = CLAMP(bweight, 0, 255);
p += new_width * 3;
}
}
free(sp);
/* free the memory allocated for vertical filter weights */
for (i = 0; i < dst->height; ++i) {
free(contrib[i].p);
}
free(contrib);
RReleaseImage(tmp);
return dst;
}