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make sharpen defaults better for screen work 

the defaults were oriented towards print output, make them more suitable
for screen work
This commit is contained in:
John Cupitt 2016-02-26 14:04:54 +00:00
parent 609e639528
commit cc9517df20
1 changed files with 19 additions and 19 deletions
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38
libvips/convolution/sharpen.c
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@ -38,6 +38,7 @@
* 24/2/16
* - swap "radius" for "sigma", allows finer control
* - allow a much greater range of parameters
* - move to defaults suitable for screen output
*/
/*
@ -323,7 +324,7 @@ vips_sharpen_class_init( VipsSharpenClass *class )
_( "Sigma of Gaussian" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, sigma ),
0.000001, 10000.0, 1.0 );
0.000001, 10000.0, 0.5 );
VIPS_ARG_DOUBLE( class, "x1", 5,
_( "x1" ),
@ -337,28 +338,28 @@ vips_sharpen_class_init( VipsSharpenClass *class )
_( "Maximum brightening" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, y2 ),
0, 1000000, 20 );
0, 1000000, 10 );
VIPS_ARG_DOUBLE( class, "y3", 7,
_( "y3" ),
_( "Maximum darkening" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, y3 ),
0, 1000000, 50 );
0, 1000000, 20 );
VIPS_ARG_DOUBLE( class, "m1", 8,
_( "m1" ),
_( "Slope for flat areas" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, m1 ),
0, 1000000, 1 );
0, 1000000, 0.0 );
VIPS_ARG_DOUBLE( class, "m2", 9,
_( "m2" ),
_( "Slope for jaggy areas" ),
VIPS_ARGUMENT_OPTIONAL_INPUT,
G_STRUCT_OFFSET( VipsSharpen, m2 ),
0, 1000000, 2 );
0, 1000000, 0.5 );
/* We used to have a radius control.
*/
@ -374,12 +375,12 @@ vips_sharpen_class_init( VipsSharpenClass *class )
static void
vips_sharpen_init( VipsSharpen *sharpen )
{
sharpen->sigma = 1.0;
sharpen->sigma = 0.5;
sharpen->x1 = 1.5;
sharpen->y2 = 20;
sharpen->y3 = 50;
sharpen->m1 = 1;
sharpen->m2 = 2;
sharpen->y2 = 10.0;
sharpen->y3 = 20.0;
sharpen->m1 = 0.0;
sharpen->m2 = 0.5;
}
/**
@ -427,20 +428,19 @@ vips_sharpen_init( VipsSharpen *sharpen )
* |
* ]|
*
* For printing, we recommend the following settings (the defaults):
* For screen output, we suggest the following settings (the defaults):
*
* |[
* sigma == 1.0
* sigma == 0.5
* x1 == 1.5
* y2 == 20 (don't brighten by more than 20 L*)
* y3 == 50 (can darken by up to 50 L*)
*
* m1 == 1 (some sharpening in flat areas)
* m2 == 2 (more sharpening in jaggy areas)
* y2 == 10 (don't brighten by more than 10 L*)
* y3 == 20 (can darken by up to 52 L*)
* m1 == 0 (no sharpening in flat areas)
* m2 == 0.5 (some sharpening in jaggy areas)
* ]|
*
* If you want more or less sharpening, we suggest you just change the m1
* and m2 parameters.
* If you want more or less sharpening, we suggest you just change the
* m2 parameter.
*
* The @sigma parameter changes the width of the fringe and can be
* adjusted according to the output printing resolution. As an approximate