fix up autofit again
A bit cleaner and simpler now, stops earlier if it can. I experimented with other ways of picking the next guess, but none were significantly better than picking the half-way point. The problem is that autosize can be very non-linear. Line breaks appear and disappear as you adjust DPI and it's possible to construct cases where it never tries the correct solution.
This commit is contained in:
John Cupitt
parent
06533d2c9e
commit
e07a1d83fb
@ -48,8 +48,8 @@
|
||||
*/
|
||||
|
||||
/*
|
||||
*/
|
||||
#define DEBUG
|
||||
*/
|
||||
|
||||
#ifdef HAVE_CONFIG_H
|
||||
#include <config.h>
|
||||
@ -189,119 +189,116 @@ vips_text_get_extents( VipsText *text, VipsRect *extents )
|
||||
return( 0 );
|
||||
}
|
||||
|
||||
/* Compare two rects and return a number estimating their difference. 0 for
|
||||
* the same, negative for first smaller, positive for first larger. One rect
|
||||
* must enclose the other.
|
||||
/* Return -ve for extents too small, 0 for a fit, +ve for extents too large.
|
||||
*/
|
||||
static int
|
||||
vips_text_rect_difference( VipsRect *a, VipsRect *b )
|
||||
vips_text_rect_difference( VipsRect *target, VipsRect *extents )
|
||||
{
|
||||
int w_diff = a->width - b->width;
|
||||
int h_diff = a->height - b->height;
|
||||
if( vips_rect_includesrect( target, extents ) ) {
|
||||
if( target->width == extents->width ||
|
||||
target->height == extents->height )
|
||||
return( 0 );
|
||||
|
||||
g_assert( vips_rect_includesrect( a, b ) ||
|
||||
vips_rect_includesrect( b, a ) );
|
||||
|
||||
/* We need the difference closest to zero.
|
||||
*/
|
||||
if( vips_rect_includesrect( a, b ) )
|
||||
/* So w and h diff must both be positive. We want the smaller
|
||||
* one.
|
||||
*/
|
||||
return( VIPS_MIN( w_diff, h_diff ) );
|
||||
else
|
||||
/* Both negative.
|
||||
*/
|
||||
return( VIPS_MAX( w_diff, h_diff ) );
|
||||
return( -1 );
|
||||
}
|
||||
else
|
||||
return( 1 );
|
||||
}
|
||||
|
||||
/* Adjust text->dpi to try to fit to the bounding box.
|
||||
*/
|
||||
static int
|
||||
vips_text_autofit( VipsText *text )
|
||||
vips_text_autofit( VipsText *text, VipsRect *out_extents )
|
||||
{
|
||||
VipsRect target;
|
||||
VipsRect extents;
|
||||
int previous_dpi;
|
||||
VipsRect previous_extents;
|
||||
int difference;
|
||||
int previous_difference;
|
||||
int previous_dpi;
|
||||
|
||||
int lower_dpi;
|
||||
int upper_dpi;
|
||||
int lower_difference;
|
||||
int upper_difference;
|
||||
VipsRect lower_extents;
|
||||
VipsRect upper_extents;
|
||||
|
||||
/* First, repeatedly double or halve dpi until we pass the correct
|
||||
* value. This will give us a lower and upper bound.
|
||||
*/
|
||||
target.width = text->width;
|
||||
target.height = text->height;
|
||||
previous_dpi = text->dpi;
|
||||
previous_difference = -1;
|
||||
previous_dpi = -1;
|
||||
|
||||
for(;;) {
|
||||
if( vips_text_get_extents( text, &extents ) )
|
||||
return( -1 );
|
||||
|
||||
target.left = extents.left;
|
||||
target.top = extents.top;
|
||||
difference = vips_text_rect_difference( &extents, &target );
|
||||
difference = vips_text_rect_difference( &target, &extents );
|
||||
|
||||
if( previous_difference == -1 )
|
||||
if( previous_dpi == -1 ) {
|
||||
previous_dpi = text->dpi;
|
||||
previous_difference = difference;
|
||||
previous_extents = extents;
|
||||
}
|
||||
|
||||
/* Too small last time, still too small.
|
||||
/* Hit the size, or we straddle the target.
|
||||
*/
|
||||
if( difference < 0 &&
|
||||
previous_difference < 0 )
|
||||
text->dpi *= 2;
|
||||
/* Too big last time, still too big.
|
||||
*/
|
||||
else if( difference > 0 &&
|
||||
previous_difference > 0 )
|
||||
text->dpi /= 2;
|
||||
/* We now straddle the target! Or both zero.
|
||||
*/
|
||||
else
|
||||
if( difference == 0 ||
|
||||
difference != previous_difference )
|
||||
break;
|
||||
|
||||
previous_difference = difference;
|
||||
previous_extents = extents;
|
||||
previous_dpi = text->dpi;
|
||||
|
||||
text->dpi = difference < 0 ? text->dpi * 2 : text->dpi / 2;
|
||||
}
|
||||
|
||||
lower_dpi = VIPS_MIN( text->dpi, previous_dpi );
|
||||
lower_difference = VIPS_MIN( difference, previous_difference );
|
||||
upper_dpi = VIPS_MAX( text->dpi, previous_dpi );
|
||||
upper_difference = VIPS_MAX( difference, previous_difference );
|
||||
if( difference < 0 ) {
|
||||
/* We've been coming down.
|
||||
*/
|
||||
lower_dpi = text->dpi;
|
||||
lower_extents = extents;
|
||||
upper_dpi = previous_dpi;
|
||||
upper_extents = previous_extents;
|
||||
}
|
||||
else {
|
||||
lower_dpi = previous_dpi;
|
||||
lower_extents = previous_extents;
|
||||
upper_dpi = text->dpi;
|
||||
upper_extents = extents;
|
||||
}
|
||||
|
||||
/* Refine lower and upper until they are almost touching, or until we
|
||||
* fit exactly.
|
||||
/* Refine lower and upper until they are almost touching.
|
||||
*/
|
||||
while( upper_dpi - lower_dpi > 1 &&
|
||||
lower_difference < 0 &&
|
||||
upper_difference > 0 ) {
|
||||
int total_difference = upper_difference - lower_difference;
|
||||
double x = (double) upper_difference / total_difference;
|
||||
int guess_dpi = (upper_dpi - lower_dpi) * x + lower_dpi;
|
||||
// guess_dpi = (upper_dpi + lower_dpi) / 2;
|
||||
|
||||
text->dpi = guess_dpi;
|
||||
difference != 0 ) {
|
||||
text->dpi = (upper_dpi + lower_dpi) / 2;
|
||||
if( vips_text_get_extents( text, &extents ) )
|
||||
return( -1 );
|
||||
|
||||
target.left = extents.left;
|
||||
target.top = extents.top;
|
||||
difference = vips_text_rect_difference( &extents, &target );
|
||||
if( difference < 0 ) {
|
||||
lower_dpi = guess_dpi;
|
||||
lower_difference = difference;
|
||||
difference = vips_text_rect_difference( &target, &extents );
|
||||
|
||||
if( difference < 0 ) {
|
||||
lower_dpi = text->dpi;
|
||||
lower_extents = extents;
|
||||
}
|
||||
else {
|
||||
upper_dpi = guess_dpi;
|
||||
upper_difference = difference;
|
||||
upper_dpi = text->dpi;
|
||||
upper_extents = extents;
|
||||
}
|
||||
}
|
||||
|
||||
if( upper_difference == 0 )
|
||||
text->dpi = upper_dpi;
|
||||
else
|
||||
if( difference > 0 ) {
|
||||
text->dpi = lower_dpi;
|
||||
*out_extents = lower_extents;
|
||||
}
|
||||
else {
|
||||
text->dpi = upper_dpi;
|
||||
*out_extents = upper_extents;
|
||||
}
|
||||
|
||||
return( 0 );
|
||||
}
|
||||
@ -334,12 +331,13 @@ vips_text_build( VipsObject *object )
|
||||
* we get a fit.
|
||||
*/
|
||||
if( vips_object_argument_isset( object, "height" ) &&
|
||||
!vips_object_argument_isset( object, "dpi" ) &&
|
||||
vips_text_autofit( text ) )
|
||||
return( -1 );
|
||||
|
||||
if( vips_text_get_extents( text, &extents ) )
|
||||
return( -1 );
|
||||
!vips_object_argument_isset( object, "dpi" ) ) {
|
||||
if( vips_text_autofit( text, &extents ) )
|
||||
return( -1 );
|
||||
}
|
||||
else
|
||||
if( vips_text_get_extents( text, &extents ) )
|
||||
return( -1 );
|
||||
|
||||
/* Can happen for "", for example.
|
||||
*/
|
||||
@ -498,7 +496,6 @@ vips_text_init( VipsText *text )
|
||||
* * @align: #VipsAlign, left/centre/right alignment
|
||||
* * @dpi: %gint, render at this resolution
|
||||
* * @spacing: %gint, space lines by this in points
|
||||
* * @gravity: #VipsGravity, gravity of text
|
||||
*
|
||||
* Draw the string @text to an image. @out is a one-band 8-bit
|
||||
* unsigned char image, with 0 for no text and 255 for text. Values inbetween
|
||||
@ -510,26 +507,23 @@ vips_text_init( VipsText *text )
|
||||
* @font is the font to render with, as a fontconfig name. Examples might be
|
||||
* "sans 12" or perhaps "bitstream charter bold 10".
|
||||
*
|
||||
* @width is the maximum number of pixels across to draw within. If the
|
||||
* generated text is wider than this, it will wrap to a new line. In this
|
||||
* case, @align can be used to set the alignment style for multi-line
|
||||
* text.
|
||||
* @width is the number of pixels to word-wrap at. Lines of text wider than
|
||||
* this will be broken at word bounaries.
|
||||
* @align can be used to set the alignment style for multi-line
|
||||
* text. Note that the output image can be wider than @width if there are no
|
||||
* word breaks.
|
||||
*
|
||||
* @height is the maximum number of pixels high the generated text can be. This
|
||||
* only takes effect when there is no font size specified, and a width is
|
||||
* provided, making a box. If a font size is provided, we render the font size
|
||||
* without any fitting to box. Bounds might be exceeded if the font size is too
|
||||
* big to be fit or wrapped inside.
|
||||
* only takes effect when @dpi is not set, and @width is set, making a box.
|
||||
* In this case, vips_text() will search for a @dpi which will just fit the
|
||||
* text into @width and @height.
|
||||
*
|
||||
* @dpi sets the resolution to render at. "sans 12" at 72 dpi draws characters
|
||||
* approximately 12 pixels high.
|
||||
* approximately 12 pixels high.
|
||||
*
|
||||
* @spacing sets the line spacing, in points. It would typicallly be something
|
||||
* like font size times 1.2.
|
||||
*
|
||||
* @gravity determines the position of the text inside the bounds. This is only
|
||||
* applied opportunistically if the bounds are bigger than the text
|
||||
*
|
||||
* See also: vips_xyz(), vips_text(), vips_gaussnoise().
|
||||
*
|
||||
* Returns: 0 on success, -1 on error
|
||||
|
||||
Loading…
Reference in New Issue
Block a user