mirror of
https://github.com/netsurf-browser/netsurf
synced 2024-11-23 14:59:47 +03:00
143 lines
4.0 KiB
C
143 lines
4.0 KiB
C
/*
|
|
* Copyright 2004 James Bursa <james@netsurf-browser.org>
|
|
* Copyright 2009 John-Mark Bell <jmb@netsurf-browser.org>
|
|
*
|
|
* This file is part of NetSurf, http://www.netsurf-browser.org/
|
|
*
|
|
* NetSurf is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; version 2 of the License.
|
|
*
|
|
* NetSurf 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 General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <assert.h>
|
|
|
|
#include "css/utils.h"
|
|
|
|
#include "desktop/options.h"
|
|
#include "utils/log.h"
|
|
|
|
/** Screen DPI in fixed point units: defaults to 90, which RISC OS uses */
|
|
css_fixed nscss_screen_dpi = F_90;
|
|
|
|
/**
|
|
* Convert an absolute CSS length to points.
|
|
*
|
|
* \param length Length to convert
|
|
* \param unit Corresponding unit
|
|
* \return length in points
|
|
*/
|
|
css_fixed nscss_len2pt(css_fixed length, css_unit unit)
|
|
{
|
|
/* Length must not be relative */
|
|
assert(unit != CSS_UNIT_EM && unit != CSS_UNIT_EX);
|
|
|
|
switch (unit) {
|
|
/* We assume the screen and any other output has the same dpi */
|
|
/* 1in = DPIpx => 1px = (72/DPI)pt */
|
|
case CSS_UNIT_PX: return FDIV(FMUL(length, F_72), nscss_screen_dpi);
|
|
/* 1in = 72pt */
|
|
case CSS_UNIT_IN: return FMUL(length, F_72);
|
|
/* 1in = 2.54cm => 1cm = (72/2.54)pt */
|
|
case CSS_UNIT_CM: return FMUL(length,
|
|
FDIV(F_72, FLTTOFIX(2.54)));
|
|
/* 1in = 25.4mm => 1mm = (72/25.4)pt */
|
|
case CSS_UNIT_MM: return FMUL(length,
|
|
FDIV(F_72, FLTTOFIX(25.4)));
|
|
case CSS_UNIT_PT: return length;
|
|
/* 1pc = 12pt */
|
|
case CSS_UNIT_PC: return FMUL(length, INTTOFIX(12));
|
|
default: break;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/**
|
|
* Convert a CSS length to pixels.
|
|
*
|
|
* \param length Length to convert
|
|
* \param unit Corresponding unit
|
|
* \param style Computed style applying to length. May be NULL if unit is
|
|
* neither em nor ex
|
|
* \return length in pixels
|
|
*/
|
|
css_fixed nscss_len2px(css_fixed length, css_unit unit,
|
|
const css_computed_style *style)
|
|
{
|
|
/* We assume the screen and any other output has the same dpi */
|
|
css_fixed px_per_unit;
|
|
|
|
assert(style != NULL || (unit != CSS_UNIT_EM && unit != CSS_UNIT_EX));
|
|
|
|
switch (unit) {
|
|
case CSS_UNIT_EM:
|
|
case CSS_UNIT_EX:
|
|
{
|
|
css_fixed font_size = 0;
|
|
css_unit font_unit = CSS_UNIT_PT;
|
|
|
|
css_computed_font_size(style, &font_size, &font_unit);
|
|
|
|
/* Convert to points */
|
|
font_size = nscss_len2pt(font_size, font_unit);
|
|
|
|
/* Clamp to configured minimum */
|
|
if (font_size < FDIV(INTTOFIX(option_font_min_size), F_10)) {
|
|
font_size = FDIV(INTTOFIX(option_font_min_size), F_10);
|
|
}
|
|
|
|
/* Convert to pixels (manually, to maximise precision)
|
|
* 1in = 72pt => 1pt = (DPI/72)px */
|
|
px_per_unit = FDIV(FMUL(font_size, nscss_screen_dpi), F_72);
|
|
|
|
/* Scale ex units: we use a fixed ratio of 1ex = 0.6em */
|
|
if (unit == CSS_UNIT_EX)
|
|
px_per_unit = FMUL(px_per_unit, FLTTOFIX(0.6));
|
|
}
|
|
break;
|
|
case CSS_UNIT_PX:
|
|
px_per_unit = F_1;
|
|
break;
|
|
/* 1in = DPIpx */
|
|
case CSS_UNIT_IN:
|
|
px_per_unit = nscss_screen_dpi;
|
|
break;
|
|
/* 1in = 2.54cm => 1cm = (DPI/2.54)px */
|
|
case CSS_UNIT_CM:
|
|
px_per_unit = FDIV(nscss_screen_dpi, FLTTOFIX(2.54));
|
|
break;
|
|
/* 1in = 25.4mm => 1mm = (DPI/25.4)px */
|
|
case CSS_UNIT_MM:
|
|
px_per_unit = FDIV(nscss_screen_dpi, FLTTOFIX(25.4));
|
|
break;
|
|
/* 1in = 72pt => 1pt = (DPI/72)px */
|
|
case CSS_UNIT_PT:
|
|
px_per_unit = FDIV(nscss_screen_dpi, F_72);
|
|
break;
|
|
/* 1pc = 12pt => 1in = 6pc => 1pc = (DPI/6)px */
|
|
case CSS_UNIT_PC:
|
|
px_per_unit = FDIV(nscss_screen_dpi, INTTOFIX(6));
|
|
break;
|
|
default:
|
|
px_per_unit = 0;
|
|
break;
|
|
}
|
|
|
|
/* Ensure we round px_per_unit to the nearest whole number of pixels:
|
|
* the use of FIXTOINT() below will truncate. */
|
|
px_per_unit += F_0_5;
|
|
|
|
/* Calculate total number of pixels */
|
|
return FMUL(length, TRUNCATEFIX(px_per_unit));
|
|
}
|
|
|