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WRaster: Changed equality/inequality comparison on floating point number

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The equality comparison (a == b) is known to be a dangerous trap
when floating-point arithmetics are involved. This patch changes
all the cases which try to do this to a safer check.
This commit is contained in:
Christophe CURIS
2013-05-11 00:07:16 +02:00
committed by Carlos R. Mafra
parent 80a59696e5
commit 8ef38e9910
3 changed files with 31 additions and 6 deletions
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21
wrlib/rotate.c
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@@ -43,12 +43,23 @@ RImage *RRotateImage(RImage * image, float angle)
int x, y;
int bpp = image->format == RRGBAFormat ? 4 : 3;
/*
* Angle steps below this value would represent a rotation
* of less than 1 pixel for a 4k wide image, so not worth
* bothering the difference. That makes it a perfect
* candidate for an Epsilon when trying to compare angle
* to known values
*/
static const float min_usable_angle = 0.00699;
angle = ((int)angle % 360) + (angle - (int)angle);
if (angle == 0.0) {
if (angle < min_usable_angle) {
/* Rotate by 0 degree */
return RCloneImage(image);
} else if (angle == 90.0) {
} else if ((angle > 90.0 - min_usable_angle) &&
(angle < 90.0 + min_usable_angle)) {
nwidth = image->height;
nheight = image->width;
@@ -91,7 +102,8 @@ RImage *RRotateImage(RImage * image, float angle)
}
}
}
} else if (angle == 180.0) {
} else if ((angle > 180.0 - min_usable_angle) &&
(angle < 180.0 + min_usable_angle)) {
nwidth = image->width;
nheight = image->height;
@@ -129,7 +141,8 @@ RImage *RRotateImage(RImage * image, float angle)
nptr--;
}
}
} else if (angle == 270.0) {
} else if ((angle > 270.0 - min_usable_angle) &&
(angle < 270.0 + min_usable_angle)) {
nwidth = image->height;
nheight = image->width;