721 lines
18 KiB
C
721 lines
18 KiB
C
/* vips_text
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*
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* Written on: 20/5/04
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* 29/7/04
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* - !HAVE_PANGOFT2 was broken, thanks Kenneth
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* 15/11/04
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* - gah, still broken, thanks Stefan
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* 5/4/06
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* - return an error for im_text( "" ) rather than trying to make an
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* empty image
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* 2/2/10
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* - gtkdoc
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* 3/6/13
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* - rewrite as a class
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* 20/9/15 leiyangyou
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* - add @spacing
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* 29/5/17
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* - don't set "font" if unset, it breaks caching
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* 16/7/17 gargsms
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* - implement auto fitting of text inside bounds
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* 12/3/18
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* - better fitting of fonts with overhanging edges, thanks Adrià
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* 26/4/18 fangqiao
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* - add fontfile option
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* 5/12/18
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* - fitting mode could set wrong dpi
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* - fitting mode leaked
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* 16/3/19
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* - add `justify`
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* - set Xoffset/Yoffset to ink left/top
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* 27/6/19
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* - fitting could occasionally terminate early [levmorozov]
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* 16/5/20 [keiviv]
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* - don't add fontfiles repeatedly
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* 12/4/21
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* - switch to cairo for text rendering
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* - add rgba flag
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* 31/10/22
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* - add @wrap
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*/
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/*
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This file is part of VIPS.
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VIPS is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program 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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA
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*/
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/*
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These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
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*/
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/*
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#define DEBUG
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /*HAVE_CONFIG_H*/
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#include <glib/gi18n-lib.h>
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#include <stdio.h>
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#include <string.h>
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#include <vips/vips.h>
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#include <vips/internal.h>
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#ifdef HAVE_PANGOCAIRO
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#include <cairo.h>
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#include <pango/pango.h>
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#include <pango/pangocairo.h>
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#ifdef HAVE_FONTCONFIG
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#include <pango/pangofc-fontmap.h>
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#include <fontconfig/fontconfig.h>
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#endif
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#include "pcreate.h"
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typedef struct _VipsText {
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VipsCreate parent_instance;
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char *text;
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char *font;
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int width;
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int height;
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int spacing;
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VipsAlign align;
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gboolean justify;
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int dpi;
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char *fontfile;
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gboolean rgba;
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VipsTextWrap wrap;
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PangoFontMap *fontmap;
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PangoContext *context;
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PangoLayout *layout;
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} VipsText;
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typedef VipsCreateClass VipsTextClass;
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G_DEFINE_TYPE( VipsText, vips_text, VIPS_TYPE_CREATE );
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/* ... single-thread vips_text_fontfiles with this.
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*/
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static GMutex *vips_text_lock = NULL;
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/* All the fontfiles we've loaded. fontconfig lets you add a fontfile
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* repeatedly, and we obviously don't want that.
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*/
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static GHashTable *vips_text_fontfiles = NULL;
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static void
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vips_text_dispose( GObject *gobject )
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{
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VipsText *text = (VipsText *) gobject;
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VIPS_UNREF( text->layout );
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VIPS_UNREF( text->context );
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G_OBJECT_CLASS( vips_text_parent_class )->dispose( gobject );
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}
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static PangoLayout *
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text_layout_new( PangoContext *context,
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const char *text, const char *font, int width, int spacing,
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VipsAlign align, VipsTextWrap wrap, gboolean justify )
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{
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PangoLayout *layout;
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PangoFontDescription *font_description;
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PangoAlignment palign;
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PangoWrapMode pwrap;
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int pwidth;
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layout = pango_layout_new( context );
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pango_layout_set_markup( layout, text, -1 );
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font_description = pango_font_description_from_string( font );
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pango_layout_set_font_description( layout, font_description );
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pango_font_description_free( font_description );
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pango_layout_set_justify( layout, justify );
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if( spacing > 0 )
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pango_layout_set_spacing( layout, spacing * PANGO_SCALE );
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switch( align ) {
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case VIPS_ALIGN_LOW:
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palign = PANGO_ALIGN_LEFT;
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break;
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case VIPS_ALIGN_CENTRE:
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palign = PANGO_ALIGN_CENTER;
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break;
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case VIPS_ALIGN_HIGH:
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palign = PANGO_ALIGN_RIGHT;
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break;
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default:
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palign = PANGO_ALIGN_LEFT;
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break;
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}
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pango_layout_set_alignment( layout, palign );
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switch( wrap ) {
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case VIPS_TEXT_WRAP_NONE:
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pwrap = PANGO_WRAP_WORD_CHAR;
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pwidth = -1;
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break;
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case VIPS_TEXT_WRAP_CHAR:
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pwrap = PANGO_WRAP_CHAR;
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pwidth = width * PANGO_SCALE;
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break;
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case VIPS_TEXT_WRAP_WORD:
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pwrap = PANGO_WRAP_WORD;
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pwidth = width * PANGO_SCALE;
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break;
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case VIPS_TEXT_WRAP_WORD_CHAR:
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default:
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pwrap = PANGO_WRAP_WORD_CHAR;
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pwidth = width * PANGO_SCALE;
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break;
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}
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pango_layout_set_wrap( layout, pwrap );
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if( pwidth > 0 )
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pango_layout_set_width( layout, width * PANGO_SCALE );
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return( layout );
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}
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static int
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vips_text_get_extents( VipsText *text, VipsRect *extents )
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{
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PangoRectangle ink_rect;
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PangoRectangle logical_rect;
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pango_cairo_font_map_set_resolution(
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PANGO_CAIRO_FONT_MAP( text->fontmap ), text->dpi );
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VIPS_UNREF( text->layout );
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if( !(text->layout = text_layout_new( text->context,
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text->text, text->font,
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text->width, text->spacing, text->align, text->wrap,
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text->justify )) )
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return( -1 );
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pango_layout_get_pixel_extents( text->layout,
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&ink_rect, &logical_rect );
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extents->left = ink_rect.x;
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extents->top = ink_rect.y;
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extents->width = ink_rect.width;
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extents->height = ink_rect.height;
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#ifdef DEBUG
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printf( "vips_text_get_extents: dpi = %d\n", text->dpi );
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printf( " ink left = %d, top = %d, width = %d, height = %d\n",
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ink_rect.x, ink_rect.y, ink_rect.width, ink_rect.height );
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printf( " logical left = %d, top = %d, width = %d, height = %d\n",
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logical_rect.x, logical_rect.y,
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logical_rect.width, logical_rect.height );
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#endif /*DEBUG*/
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return( 0 );
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}
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/* Return -ve for extents too small, +ve for extents too large.
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*/
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static int
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vips_text_rect_difference( VipsRect *target, VipsRect *extents )
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{
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if( vips_rect_includesrect( target, extents ) )
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return( -1 );
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else
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return( 1 );
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}
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/* Adjust text->dpi to try to fit to the bounding box.
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*/
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static int
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vips_text_autofit( VipsText *text )
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{
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VipsRect target;
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VipsRect extents;
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int difference;
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int previous_difference;
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int previous_dpi;
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int lower_dpi;
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int upper_dpi;
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/* First, repeatedly double or halve dpi until we pass the correct
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* value. This will give us a lower and upper bound.
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*/
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target.left = 0;
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target.top = 0;
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target.width = text->width;
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target.height = text->height;
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previous_dpi = -1;
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previous_difference = 0;
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#ifdef DEBUG
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printf( "vips_text_autofit: "
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"target left = %d, top = %d, width = %d, height = %d\n",
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target.left, target.top, target.width, target.height );
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#endif /*DEBUG*/
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for(;;) {
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if( vips_text_get_extents( text, &extents ) )
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return( -1 );
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target.left = extents.left;
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target.top = extents.top;
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difference = vips_text_rect_difference( &target, &extents );
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if( previous_dpi == -1 ) {
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previous_dpi = text->dpi;
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previous_difference = difference;
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}
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/* Stop if we straddle the target.
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*/
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if( difference != previous_difference )
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break;
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previous_difference = difference;
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previous_dpi = text->dpi;
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text->dpi = difference < 0 ? text->dpi * 2 : text->dpi / 2;
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/* This can happen with fixed-size fonts.
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*/
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if( text->dpi < 2 ||
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text->dpi > 10000 )
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break;
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}
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if( difference < 0 ) {
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/* We've been coming down.
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*/
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lower_dpi = text->dpi;
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upper_dpi = previous_dpi;
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}
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else {
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lower_dpi = previous_dpi;
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upper_dpi = text->dpi;
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}
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#ifdef DEBUG
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printf( "vips_text_autofit: lower dpi = %d, upper dpi = %d\n",
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lower_dpi, upper_dpi );
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#endif /*DEBUG*/
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/* Refine lower and upper until they are almost touching.
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*/
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while( upper_dpi - lower_dpi > 1 &&
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difference != 0 ) {
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text->dpi = (upper_dpi + lower_dpi) / 2;
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if( vips_text_get_extents( text, &extents ) )
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return( -1 );
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target.left = extents.left;
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target.top = extents.top;
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difference = vips_text_rect_difference( &target, &extents );
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if( difference < 0 )
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lower_dpi = text->dpi;
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else
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upper_dpi = text->dpi;
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}
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/* If we've hit the target exactly and quit the loop, diff will be 0
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* and we can use upper. Otherwise we are straddling the target and we
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* must take lower.
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*/
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if( difference == 0 )
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text->dpi = upper_dpi;
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else
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text->dpi = lower_dpi;
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g_object_set( text, "autofit_dpi", text->dpi, NULL );
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#ifdef DEBUG
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printf( "vips_text_autofit: final dpi = %d\n", text->dpi );
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#endif /*DEBUG*/
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return( 0 );
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}
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static int
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vips_text_build( VipsObject *object )
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{
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VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
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VipsCreate *create = VIPS_CREATE( object );
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VipsText *text = (VipsText *) object;
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VipsImage **t = (VipsImage **) vips_object_local_array( object, 3 );
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VipsRect extents;
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VipsImage *image;
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cairo_surface_t *surface;
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cairo_t *cr;
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cairo_status_t status;
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if( VIPS_OBJECT_CLASS( vips_text_parent_class )->build( object ) )
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return( -1 );
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if( !pango_parse_markup( text->text, -1, 0, NULL, NULL, NULL, NULL ) ) {
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vips_error( class->nickname,
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"%s", _( "invalid markup in text" ) );
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return( -1 );
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}
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text->fontmap = pango_cairo_font_map_get_default();
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text->context = pango_font_map_create_context(
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PANGO_FONT_MAP( text->fontmap ) );
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g_mutex_lock( vips_text_lock );
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if( !vips_text_fontfiles )
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vips_text_fontfiles =
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g_hash_table_new( g_str_hash, g_str_equal );
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#ifdef HAVE_FONTCONFIG
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if( text->fontfile &&
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!g_hash_table_lookup( vips_text_fontfiles, text->fontfile ) ) {
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/* This can fail if you eg. add the same font from two
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* different files. Just warn.
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*/
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if( !FcConfigAppFontAddFile( NULL,
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(const FcChar8 *) text->fontfile ) )
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g_warning( _( "unable to load fontfile \"%s\"" ),
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text->fontfile );
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g_hash_table_insert( vips_text_fontfiles,
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text->fontfile,
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g_strdup( text->fontfile ) );
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/* We need to inform that pango should invalidate its
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* fontconfig cache whenever any changes are made.
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*/
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if( PANGO_IS_FC_FONT_MAP( text->fontmap ) )
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pango_fc_font_map_cache_clear(
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PANGO_FC_FONT_MAP( text->fontmap ) );
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}
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#else /*!HAVE_FONTCONFIG*/
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if( text->fontfile )
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g_warning( "%s",
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_( "ignoring fontfile (no fontconfig support)" ) );
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#endif /*HAVE_FONTCONFIG*/
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g_mutex_unlock( vips_text_lock );
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/* If our caller set height and not dpi, we adjust dpi until
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* we get a fit.
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*/
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if( vips_object_argument_isset( object, "height" ) &&
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!vips_object_argument_isset( object, "dpi" ) ) {
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if( vips_text_autofit( text ) )
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return( -1 );
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}
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/* Layout. Can fail for "", for example.
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*/
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if( vips_text_get_extents( text, &extents ) )
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return( -1 );
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if( extents.width == 0 ||
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extents.height == 0 ) {
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vips_error( class->nickname, "%s", _( "no text to render" ) );
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return( -1 );
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}
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image = t[0] = vips_image_new_memory();
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vips_image_init_fields( image,
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extents.width, extents.height, 4,
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VIPS_FORMAT_UCHAR, VIPS_CODING_NONE,
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VIPS_INTERPRETATION_sRGB,
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text->dpi / 25.4, text->dpi / 25.4 );
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image->Xoffset = extents.left;
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image->Yoffset = extents.top;
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if( vips_image_pipelinev( image, VIPS_DEMAND_STYLE_ANY, NULL ) ||
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vips_image_write_prepare( image ) )
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return( -1 );
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surface = cairo_image_surface_create_for_data(
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VIPS_IMAGE_ADDR( image, 0, 0 ),
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CAIRO_FORMAT_ARGB32,
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image->Xsize, image->Ysize,
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VIPS_IMAGE_SIZEOF_LINE( image ) );
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status = cairo_surface_status( surface );
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if( status ) {
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cairo_surface_destroy( surface );
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vips_error( class->nickname,
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"%s", cairo_status_to_string( status ) );
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return( -1 );
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}
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cr = cairo_create( surface );
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cairo_surface_destroy( surface );
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cairo_translate( cr, -extents.left, -extents.top );
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pango_cairo_show_layout( cr, text->layout );
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cairo_destroy( cr );
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if( text->rgba ) {
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int y;
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/* Cairo makes pre-multipled BRGA -- we must byteswap and
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* unpremultiply.
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*/
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for( y = 0; y < image->Ysize; y++ )
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vips__premultiplied_bgra2rgba(
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(guint32 *)
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VIPS_IMAGE_ADDR( image, 0, y ),
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image->Xsize );
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}
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else {
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/* We just want the alpha channel.
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*/
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if( vips_extract_band( image, &t[1], 3, NULL ) ||
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vips_copy( t[1], &t[2],
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"interpretation", VIPS_INTERPRETATION_MULTIBAND,
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NULL ) )
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return( -1 );
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image = t[2];
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}
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if( vips_image_write( image, create->out ) )
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return( -1 );
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return( 0 );
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}
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|
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static void *
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vips_text_make_lock( void *client )
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{
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if( !vips_text_lock )
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vips_text_lock = vips_g_mutex_new();
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return( NULL );
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}
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|
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static void
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vips_text_class_init( VipsTextClass *class )
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{
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GObjectClass *gobject_class = G_OBJECT_CLASS( class );
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VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
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static GOnce once = G_ONCE_INIT;
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VIPS_ONCE( &once, vips_text_make_lock, NULL );
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gobject_class->dispose = vips_text_dispose;
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gobject_class->set_property = vips_object_set_property;
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gobject_class->get_property = vips_object_get_property;
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vobject_class->nickname = "text";
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vobject_class->description = _( "make a text image" );
|
|
vobject_class->build = vips_text_build;
|
|
|
|
VIPS_ARG_STRING( class, "text", 4,
|
|
_( "Text" ),
|
|
_( "Text to render" ),
|
|
VIPS_ARGUMENT_REQUIRED_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, text ),
|
|
NULL );
|
|
|
|
VIPS_ARG_STRING( class, "font", 5,
|
|
_( "Font" ),
|
|
_( "Font to render with" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, font ),
|
|
NULL );
|
|
|
|
VIPS_ARG_INT( class, "width", 6,
|
|
_( "Width" ),
|
|
_( "Maximum image width in pixels" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, width ),
|
|
0, VIPS_MAX_COORD, 0 );
|
|
|
|
VIPS_ARG_INT( class, "height", 7,
|
|
_( "Height" ),
|
|
_( "Maximum image height in pixels" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, height ),
|
|
0, VIPS_MAX_COORD, 0 );
|
|
|
|
VIPS_ARG_ENUM( class, "align", 8,
|
|
_( "Align" ),
|
|
_( "Align on the low, centre or high edge" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, align ),
|
|
VIPS_TYPE_ALIGN, VIPS_ALIGN_LOW );
|
|
|
|
VIPS_ARG_BOOL( class, "justify", 9,
|
|
_( "Justify" ),
|
|
_( "Justify lines" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, justify ),
|
|
FALSE );
|
|
|
|
VIPS_ARG_INT( class, "dpi", 10,
|
|
_( "DPI" ),
|
|
_( "DPI to render at" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, dpi ),
|
|
1, 1000000, 72 );
|
|
|
|
VIPS_ARG_INT( class, "autofit_dpi", 11,
|
|
_( "Autofit DPI" ),
|
|
_( "DPI selected by autofit" ),
|
|
VIPS_ARGUMENT_OPTIONAL_OUTPUT,
|
|
G_STRUCT_OFFSET( VipsText, dpi ),
|
|
1, 1000000, 72 );
|
|
|
|
VIPS_ARG_INT( class, "spacing", 12,
|
|
_( "Spacing" ),
|
|
_( "Line spacing" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, spacing ),
|
|
0, 1000000, 0 );
|
|
|
|
VIPS_ARG_STRING( class, "fontfile", 13,
|
|
_( "Font file" ),
|
|
_( "Load this font file" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, fontfile ),
|
|
NULL );
|
|
|
|
VIPS_ARG_BOOL( class, "rgba", 14,
|
|
_( "RGBA" ),
|
|
_( "Enable RGBA output" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, rgba ),
|
|
FALSE );
|
|
|
|
VIPS_ARG_ENUM( class, "wrap", 15,
|
|
_( "Wrap" ),
|
|
_( "Wrap lines on word or character boundaries" ),
|
|
VIPS_ARGUMENT_OPTIONAL_INPUT,
|
|
G_STRUCT_OFFSET( VipsText, wrap ),
|
|
VIPS_TYPE_TEXT_WRAP, VIPS_TEXT_WRAP_WORD );
|
|
|
|
}
|
|
|
|
static void
|
|
vips_text_init( VipsText *text )
|
|
{
|
|
text->align = VIPS_ALIGN_LOW;
|
|
text->dpi = 72;
|
|
text->wrap = VIPS_TEXT_WRAP_WORD;
|
|
VIPS_SETSTR( text->font, "sans 12" );
|
|
}
|
|
|
|
#endif /*HAVE_PANGOCAIRO*/
|
|
|
|
/**
|
|
* vips_text:
|
|
* @out: (out): output image
|
|
* @text: utf-8 text string to render
|
|
* @...: %NULL-terminated list of optional named arguments
|
|
*
|
|
* Optional arguments:
|
|
*
|
|
* * @font: %gchararray, font to render with
|
|
* * @fontfile: %gchararray, load this font file
|
|
* * @width: %gint, image should be no wider than this many pixels
|
|
* * @height: %gint, image should be no higher than this many pixels
|
|
* * @align: #VipsAlign, set justification alignment
|
|
* * @justify: %gboolean, justify lines
|
|
* * @dpi: %gint, render at this resolution
|
|
* * @autofit_dpi: %gint, read out auto-fitted DPI
|
|
* * @rgba: %gboolean, enable RGBA output
|
|
* * @spacing: %gint, space lines by this in points
|
|
* * @wrap: #VipsTextWrap, wrap lines on characters or words
|
|
*
|
|
* Draw the string @text to an image. @out is normally a one-band 8-bit
|
|
* unsigned char image, with 0 for no text and 255 for text. Values between
|
|
* are used for anti-aliasing.
|
|
*
|
|
* Set @rgba to enable RGBA output. This is useful for colour emoji rendering,
|
|
* or support for pango markup features like `<span
|
|
* foreground="red">Red!</span>`.
|
|
*
|
|
* @text is the text to render as a UTF-8 string. It can contain Pango markup,
|
|
* for example `<i>The</i>Guardian`.
|
|
*
|
|
* @font is the font to render with, as a fontconfig name. Examples might be
|
|
* `sans 12` or perhaps `bitstream charter bold 10`.
|
|
*
|
|
* You can specify a font to load with @fontfile. You'll need to also set the
|
|
* name of the font with @font.
|
|
*
|
|
* @width is the number of pixels to word-wrap at. By default, lines of text
|
|
* wider than this will be broken at word boundaries.
|
|
* Use @wrap to set lines to wrap on word or character boundaries, or to
|
|
* disable line breaks.
|
|
*
|
|
* Set @justify to turn on line justification.
|
|
* @align can be used to set the alignment style for multi-line
|
|
* text to the low (left) edge centre, or high (right) edge. Note that the
|
|
* output image can be wider than @width if there are no
|
|
* word breaks, or narrower if the lines don't break exactly at @width.
|
|
*
|
|
* @height is the maximum number of pixels high the generated text can be. This
|
|
* 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 and set of line breaks
|
|
* which will just fit the text into @width and @height.
|
|
*
|
|
* You can use @autofit_dpi to read out the DPI selected by auto fit.
|
|
*
|
|
* @dpi sets the resolution to render at. "sans 12" at 72 dpi draws characters
|
|
* approximately 12 pixels high.
|
|
*
|
|
* @spacing sets the line spacing, in points. It would typically be something
|
|
* like font size times 1.2.
|
|
*
|
|
* You can read the coordinate of the top edge of the character from `Xoffset`
|
|
* / `Yoffset`. This can be helpful if you need to line up the output of
|
|
* several vips_text().
|
|
*
|
|
* See also: vips_bandjoin(), vips_composite().
|
|
*
|
|
* Returns: 0 on success, -1 on error
|
|
*/
|
|
int
|
|
vips_text( VipsImage **out, const char *text, ... )
|
|
{
|
|
va_list ap;
|
|
int result;
|
|
|
|
va_start( ap, text );
|
|
result = vips_call_split( "text", ap, out, text );
|
|
va_end( ap );
|
|
|
|
return( result );
|
|
}
|