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/* |
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* Copyright 2004 James Bursa |
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* Copyright 2009 John-Mark Bell |
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* |
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* This file is part of NetSurf, http://www.netsurf-browser.org/ |
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* |
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* NetSurf is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation; version 2 of the License. |
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* |
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* NetSurf is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program. If not, see . |
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*/ |
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#include |
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#include "css/utils.h" |
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#include "desktop/options.h" |
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#include "utils/log.h" |
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/** Screen DPI in fixed point units: defaults to 90, which RISC OS uses */ |
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css_fixed nscss_screen_dpi = F_90; |
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/** |
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* Convert an absolute CSS length to points. |
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* |
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* \param length Length to convert |
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* \param unit Corresponding unit |
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* \return length in points |
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*/ |
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css_fixed nscss_len2pt(css_fixed length, css_unit unit) |
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{ |
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/* Length must not be relative */ |
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assert(unit != CSS_UNIT_EM && unit != CSS_UNIT_EX); |
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switch (unit) { |
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/* We assume the screen and any other output has the same dpi */ |
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/* 1in = DPIpx => 1px = (72/DPI)pt */ |
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case CSS_UNIT_PX: return FDIV(FMUL(length, F_72), nscss_screen_dpi); |
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/* 1in = 72pt */ |
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case CSS_UNIT_IN: return FMUL(length, F_72); |
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/* 1in = 2.54cm => 1cm = (72/2.54)pt */ |
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case CSS_UNIT_CM: return FMUL(length, |
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FDIV(F_72, FLTTOFIX(2.54))); |
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/* 1in = 25.4mm => 1mm = (72/25.4)pt */ |
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case CSS_UNIT_MM: return FMUL(length, |
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FDIV(F_72, FLTTOFIX(25.4))); |
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case CSS_UNIT_PT: return length; |
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/* 1pc = 12pt */ |
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case CSS_UNIT_PC: return FMUL(length, INTTOFIX(12)); |
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default: break; |
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} |
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return 0; |
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} |
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/** |
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* Convert a CSS length to pixels. |
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* |
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* \param length Length to convert |
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* \param unit Corresponding unit |
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* \param style Computed style applying to length. May be NULL if unit is |
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* neither em nor ex |
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* \return length in pixels |
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*/ |
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css_fixed nscss_len2px(css_fixed length, css_unit unit, |
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const css_computed_style *style) |
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{ |
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ashmew2 |
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/* We assume the screen and ay other output has the same dpi */ |
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sourcerer |
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css_fixed px_per_unit; |
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assert(style != NULL || (unit != CSS_UNIT_EM && unit != CSS_UNIT_EX)); |
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switch (unit) { |
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case CSS_UNIT_EM: |
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case CSS_UNIT_EX: |
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{ |
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css_fixed font_size = 0; |
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css_unit font_unit = CSS_UNIT_PT; |
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css_computed_font_size(style, &font_size, &font_unit); |
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/* Convert to points */ |
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font_size = nscss_len2pt(font_size, font_unit); |
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/* Clamp to configured minimum */ |
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if (font_size < FDIV(INTTOFIX(nsoption_int(font_min_size)), F_10)) { |
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font_size = FDIV(INTTOFIX(nsoption_int(font_min_size)), F_10); |
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} |
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/* Convert to pixels (manually, to maximise precision) |
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* 1in = 72pt => 1pt = (DPI/72)px */ |
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px_per_unit = FDIV(FMUL(font_size, nscss_screen_dpi), F_72); |
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/* Scale ex units: we use a fixed ratio of 1ex = 0.6em */ |
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if (unit == CSS_UNIT_EX) |
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px_per_unit = FMUL(px_per_unit, FLTTOFIX(0.6)); |
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} |
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break; |
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case CSS_UNIT_PX: |
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px_per_unit = F_1; |
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break; |
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/* 1in = DPIpx */ |
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case CSS_UNIT_IN: |
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px_per_unit = nscss_screen_dpi; |
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break; |
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/* 1in = 2.54cm => 1cm = (DPI/2.54)px */ |
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case CSS_UNIT_CM: |
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px_per_unit = FDIV(nscss_screen_dpi, FLTTOFIX(2.54)); |
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break; |
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/* 1in = 25.4mm => 1mm = (DPI/25.4)px */ |
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case CSS_UNIT_MM: |
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px_per_unit = FDIV(nscss_screen_dpi, FLTTOFIX(25.4)); |
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break; |
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/* 1in = 72pt => 1pt = (DPI/72)px */ |
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case CSS_UNIT_PT: |
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px_per_unit = FDIV(nscss_screen_dpi, F_72); |
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break; |
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/* 1pc = 12pt => 1in = 6pc => 1pc = (DPI/6)px */ |
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case CSS_UNIT_PC: |
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px_per_unit = FDIV(nscss_screen_dpi, INTTOFIX(6)); |
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break; |
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default: |
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px_per_unit = 0; |
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break; |
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} |
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/* Ensure we round px_per_unit to the nearest whole number of pixels: |
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* the use of FIXTOINT() below will truncate. */ |
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px_per_unit += F_0_5; |
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/* Calculate total number of pixels */ |
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return FMUL(length, TRUNCATEFIX(px_per_unit)); |
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} |
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