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Fix overflow issues in image rotation

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Also, do some refactoring to simplify code.
* src/dispextern.h (INIT_MATRIX, COPY_MATRIX, MULT_MATRICES): Remove.
* src/image.c (matrix3x3): New type, replacing all uses of 3x3 double.
(matrix3x3_copy, matrix3x3_mult): New functions, replacing
COPY_MATRIX, MULT_MATRICES.  Replace INIT_MATRIX by C initializers.
(image_set_rotation): Use Fmod to avoid undefined behavior on
double-to-int conversion and to reduce bignum rotations correctly.
(image_set_crop): Finish up previous correction, by not re-setting
width and height if compute_image_size has set them.
Prefer shifting right by 1 to dividing by 2 if either will do.
This commit is contained in:
Paul Eggert 2019-06-06 08:09:58 -07:00
parent e29fb7dfba
commit 7c26e0b18d
2 changed files with 77 additions and 93 deletions
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21
src/dispextern.h
View file

@ -2988,26 +2988,9 @@ struct redisplay_interface
#ifdef HAVE_WINDOW_SYSTEM
# if defined USE_CAIRO || defined HAVE_XRENDER || defined HAVE_NS || defined HAVE_NTGUI
# if (defined USE_CAIRO || defined HAVE_XRENDER \
|| defined HAVE_NS || defined HAVE_NTGUI)
# define HAVE_NATIVE_TRANSFORMS
# define INIT_MATRIX(m) \
for (int i = 0 ; i < 3 ; i++) \
for (int j = 0 ; j < 3 ; j++) \
m[i][j] = (i == j) ? 1 : 0;
# define COPY_MATRIX(a, b) \
for (int i = 0 ; i < 3 ; i++) \
for (int j = 0 ; j < 3 ; j++) \
b[i][j] = a[i][j];
# define MULT_MATRICES(a, b, result) \
for (int i = 0 ; i < 3 ; i++) \
for (int j = 0 ; j < 3 ; j++) { \
double sum = 0; \
for (int k = 0 ; k < 3 ; k++) \
sum += a[k][j] * b[i][k]; \
result[i][j] = sum;}
# endif
/* Structure describing an image. Specific image formats like XBM are

149
src/image.c
View file

@ -1942,8 +1942,29 @@ compute_image_size (size_t width, size_t height,
}
#endif /* HAVE_IMAGEMAGICK || HAVE_NATIVE_TRANSFORMS */
typedef double matrix3x3[3][3];
static void
image_set_rotation (struct image *img, double tm[3][3])
matrix3x3_copy (matrix3x3 a, matrix3x3 b)
{
memcpy (b, a, sizeof (matrix3x3));
}
static void
matrix3x3_mult (matrix3x3 a, matrix3x3 b, matrix3x3 result)
{
for (int i = 0; i < 3; i++)
for (int j = 0; j < 3; j++)
{
double sum = 0;
for (int k = 0; k < 3; k++)
sum += a[i][k] * b[k][j];
result[i][j] = sum;
}
}
static void
image_set_rotation (struct image *img, matrix3x3 tm)
{
#ifdef HAVE_NATIVE_TRANSFORMS
# ifdef HAVE_IMAGEMAGICK
@ -1957,19 +1978,21 @@ image_set_rotation (struct image *img, double tm[3][3])
return;
# endif
Lisp_Object value;
double t[3][3], rot[3][3], tmp[3][3], tmp2[3][3];
int rotation, cos_r, sin_r, width, height;
value = image_spec_value (img->spec, QCrotation, NULL);
Lisp_Object value = image_spec_value (img->spec, QCrotation, NULL);
if (! NUMBERP (value))
return;
rotation = XFLOATINT (value);
rotation = rotation % 360;
if (rotation < 0)
rotation += 360;
Lisp_Object reduced_angle = Fmod (value, make_fixnum (360));
if (! FLOATP (reduced_angle))
rotation = XFIXNUM (reduced_angle);
else
{
rotation = XFLOAT_DATA (reduced_angle);
if (rotation != XFLOAT_DATA (reduced_angle))
goto not_a_multiple_of_90;
}
if (rotation == 0)
return;
@ -2000,32 +2023,31 @@ image_set_rotation (struct image *img, double tm[3][3])
}
else
{
image_error ("Native image rotation only supports multiples of 90 degrees");
not_a_multiple_of_90:
image_error ("Native image rotation supports "
"only multiples of 90 degrees");
return;
}
/* Translate so (0, 0) is in the centre of the image. */
INIT_MATRIX (t);
t[2][0] = img->width/2;
t[2][1] = img->height/2;
MULT_MATRICES (tm, t, tmp);
/* Translate so (0, 0) is in the center of the image. */
matrix3x3 t
= { [0][0] = 1,
[1][1] = 1,
[2][0] = img->width >> 1, [2][1] = img->height >> 1, [2][2] = 1 };
matrix3x3 tmp;
matrix3x3_mult (t, tm, tmp);
/* Rotate. */
INIT_MATRIX (rot);
rot[0][0] = cos_r;
rot[1][0] = sin_r;
rot[0][1] = - sin_r;
rot[1][1] = cos_r;
MULT_MATRICES (tmp, rot, tmp2);
matrix3x3 rot = { [0][0] = cos_r, [0][1] = -sin_r,
[1][0] = sin_r, [1][1] = cos_r,
[2][2] = 1 };
matrix3x3 tmp2;
matrix3x3_mult (rot, tmp, tmp2);
/* Translate back. */
INIT_MATRIX (t);
t[2][0] = - width/2;
t[2][1] = - height/2;
MULT_MATRICES (tmp2, t, tm);
t[2][0] = - (width >> 1);
t[2][1] = - (height >> 1);
matrix3x3_mult (t, tmp2, tm);
img->width = width;
img->height = height;
@ -2033,7 +2055,7 @@ image_set_rotation (struct image *img, double tm[3][3])
}
static void
image_set_crop (struct image *img, double tm[3][3])
image_set_crop (struct image *img, matrix3x3 tm)
{
int width, height;
compute_image_size (img->width, img->height, img->spec, &width, &height);
@ -2052,39 +2074,29 @@ image_set_crop (struct image *img, double tm[3][3])
return;
# endif
double m[3][3], tmp[3][3];
int left, top;
Lisp_Object x = Qnil;
Lisp_Object y = Qnil;
Lisp_Object w = Qnil;
Lisp_Object h = Qnil;
Lisp_Object crop = image_spec_value (img->spec, QCcrop, NULL);
if (!CONSP (crop))
return;
else
Lisp_Object w = XCAR (crop), h = Qnil, x = Qnil, y = Qnil;
crop = XCDR (crop);
if (CONSP (crop))
{
w = XCAR (crop);
h = XCAR (crop);
crop = XCDR (crop);
if (CONSP (crop))
{
h = XCAR (crop);
x = XCAR (crop);
crop = XCDR (crop);
if (CONSP (crop))
{
x = XCAR (crop);
crop = XCDR (crop);
if (CONSP (crop))
y = XCAR (crop);
}
y = XCAR (crop);
}
}
if (FIXNATP (w) && XFIXNAT (w) < img->width)
width = XFIXNAT (w);
else
width = img->width;
int left;
if (TYPE_RANGED_FIXNUMP (int, x))
{
left = XFIXNUM (x);
@ -2092,13 +2104,11 @@ image_set_crop (struct image *img, double tm[3][3])
left = img->width - width + left;
}
else
left = (img->width - width)/2;
left = (img->width - width) >> 1;
if (FIXNATP (h) && XFIXNAT (h) < img->height)
height = XFIXNAT (h);
else
height = img->height;
int top;
if (TYPE_RANGED_FIXNUMP (int, y))
{
top = XFIXNUM (y);
@ -2106,7 +2116,7 @@ image_set_crop (struct image *img, double tm[3][3])
top = img->height - height + top;
}
else
top = (img->height - height)/2;
top = (img->height - height) >> 1;
/* Negative values operate from the right and bottom of the image
instead of the left and top. */
@ -2128,12 +2138,11 @@ image_set_crop (struct image *img, double tm[3][3])
if (height + top > img->height)
height = img->height - top;
INIT_MATRIX (m);
m[2][0] = left;
m[2][1] = top;
MULT_MATRICES (tm, m, tmp);
COPY_MATRIX (tmp, tm);
matrix3x3 tmp, m = { [0][0] = 1,
[1][1] = 1,
[2][0] = left, [2][1] = top, [2][2] = 1 };
matrix3x3_mult (m, tm, tmp);
matrix3x3_copy (tmp, tm);
img->width = width;
img->height = height;
@ -2141,7 +2150,7 @@ image_set_crop (struct image *img, double tm[3][3])
}
static void
image_set_size (struct image *img, double tm[3][3])
image_set_size (struct image *img, matrix3x3 tm)
{
#ifdef HAVE_NATIVE_TRANSFORMS
# ifdef HAVE_IMAGEMAGICK
@ -2160,18 +2169,12 @@ image_set_size (struct image *img, double tm[3][3])
compute_image_size (img->width, img->height, img->spec, &width, &height);
# if defined (HAVE_NS) || defined (HAVE_XRENDER)
double rm[3][3], tmp[3][3];
double xscale, yscale;
double xscale = img->width / (double) width;
double yscale = img->height / (double) height;
xscale = img->width / (double) width;
yscale = img->height / (double) height;
INIT_MATRIX (rm);
rm[0][0] = xscale;
rm[1][1] = yscale;
MULT_MATRICES (tm, rm, tmp);
COPY_MATRIX (tmp, tm);
matrix3x3 tmp, rm = { [0][0] = xscale, [1][1] = yscale, [2][2] = 1 };
matrix3x3_mult (rm, tm, tmp);
matrix3x3_copy (tmp, tm);
img->width = width;
img->height = height;
@ -2187,7 +2190,7 @@ image_set_size (struct image *img, double tm[3][3])
}
static void
image_set_transform (struct frame *f, struct image *img, double matrix[3][3])
image_set_transform (struct frame *f, struct image *img, matrix3x3 matrix)
{
/* TODO: Add MS Windows support. */
#ifdef HAVE_NATIVE_TRANSFORMS
@ -2273,9 +2276,7 @@ lookup_image (struct frame *f, Lisp_Object spec)
int relief_bound;
#ifdef HAVE_NATIVE_TRANSFORMS
double transform_matrix[3][3];
INIT_MATRIX (transform_matrix);
matrix3x3 transform_matrix = { [0][0] = 1, [1][1] = 1, [2][2] = 1 };
image_set_size (img, transform_matrix);
image_set_crop (img, transform_matrix);
image_set_rotation (img, transform_matrix);