src/plugins/litehtml_viewer/lh_widget_text.cpp

   1 /*
   2  * Claws Mail -- A GTK+ based, lightweight, and fast e-mail client
   3  * Copyright(C) 2019 the Claws Mail Team
   4  *
   5  * litehtml callbacks related to text rendering
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write tothe Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  */
  19
  20 #include "config.h"
  21
  22 #include <glib.h>
  23
  24 #include "litehtml/litehtml.h"
  25
  26 #include "lh_widget.h"
  27
  28 litehtml::uint_ptr lh_widget::create_font( const litehtml::tchar_t* faceName, int size, int weight, litehtml::font_style italic, unsigned int decoration, litehtml::font_metrics* fm )
  29 {
  30         PangoFontDescription *desc =
  31                 pango_font_description_from_string(faceName);
  32
  33         pango_font_description_set_size(desc, size * PANGO_SCALE);
  34         pango_font_description_set_weight(desc, (PangoWeight)weight);
  35
  36         if (italic == litehtml::fontStyleItalic)
  37                 pango_font_description_set_style(desc, PANGO_STYLE_ITALIC);
  38         else
  39                 pango_font_description_set_style(desc, PANGO_STYLE_NORMAL);
  40
  41         if(fm != NULL) {
  42                 PangoContext *context = gtk_widget_get_pango_context(m_drawing_area);
  43                 PangoFontMetrics *metrics = pango_context_get_metrics(
  44                                 context, desc,
  45                                 pango_context_get_language(context));
  46                 PangoLayout *x_layout;
  47                 PangoRectangle rect;
  48
  49                 x_layout = pango_layout_new(context);
  50                 pango_layout_set_font_description(x_layout, desc);
  51                 pango_layout_set_text(x_layout, "x", -1);
  52                 pango_layout_get_pixel_extents(x_layout, NULL, &rect);
  53
  54                 fm->ascent              = pango_font_metrics_get_ascent(metrics) / PANGO_SCALE;
  55                 fm->descent             = pango_font_metrics_get_descent(metrics) / PANGO_SCALE;
  56                 fm->height              = fm->ascent + fm->descent;
  57                 fm->x_height    = rect.height;
  58
  59                 g_object_unref(x_layout);
  60                 pango_font_metrics_unref(metrics);
  61         }
  62
  63         pango_font *ret = new pango_font;
  64         ret->font = desc;
  65         ret->strikethrough = (decoration & litehtml::font_decoration_linethrough) ? true : false;
  66         ret->underline = (decoration & litehtml::font_decoration_underline) ? true : false;
  67
  68         return (litehtml::uint_ptr) ret;
  69 }
  70
  71 void lh_widget::delete_font( litehtml::uint_ptr hFont )
  72 {
  73         pango_font *fnt = (pango_font *)hFont;
  74
  75         if (fnt != NULL) {
  76                 pango_font_description_free(fnt->font);
  77                 delete fnt;
  78         }
  79 }
  80
  81 int lh_widget::text_width( const litehtml::tchar_t* text, litehtml::uint_ptr hFont )
  82 {
  83         pango_font *fnt = (pango_font *) hFont;
  84         PangoContext *context = gtk_widget_get_pango_context(m_drawing_area);
  85         PangoLayout *layout = pango_layout_new(context);
  86         PangoRectangle rect;
  87
  88         if (fnt)
  89                 pango_layout_set_font_description(layout, fnt->font);
  90
  91         pango_layout_set_text(layout, text, -1);
  92         pango_layout_get_pixel_extents(layout, NULL, &rect);
  93
  94         g_object_unref(layout);
  95
  96         return rect.width;
  97 }
  98
  99 void lh_widget::draw_text( litehtml::uint_ptr hdc, const litehtml::tchar_t* text, litehtml::uint_ptr hFont, litehtml::web_color color, const litehtml::position& pos )
 100 {
 101         pango_font *fnt = (pango_font *)hFont;
 102         cairo_t *cr = (cairo_t *)hdc;
 103         PangoLayout *layout = pango_cairo_create_layout(cr);
 104         PangoContext *context = pango_layout_get_context(layout);
 105         GdkScreen* screen = gdk_screen_get_default();
 106         double dpi = gdk_screen_get_resolution(screen);
 107
 108         pango_cairo_context_set_resolution(context, dpi);
 109
 110         if (fnt != NULL) {
 111                 /* Set font */
 112                 pango_layout_set_font_description(layout, fnt->font);
 113
 114                 /* Set additional font attributes */
 115                 if (fnt->underline || fnt->strikethrough) {
 116                         PangoAttrList *attr_list = pango_attr_list_new();
 117                         PangoUnderline ul;
 118
 119                         if (fnt->underline )
 120                                 ul = PANGO_UNDERLINE_SINGLE;
 121                         else
 122                                 ul = PANGO_UNDERLINE_NONE;
 123
 124                         pango_attr_list_insert(attr_list,
 125                                         pango_attr_underline_new(ul));
 126                         pango_attr_list_insert(attr_list,
 127                                         pango_attr_strikethrough_new(fnt->strikethrough));
 128
 129                         pango_layout_set_attributes(layout, attr_list);
 130                         pango_attr_list_unref(attr_list);
 131                 }
 132         }
 133
 134         /* Set actual text content */
 135         pango_layout_set_text(layout, text, -1);
 136
 137         cairo_save(cr);
 138
 139         /* Draw the text where it's supposed to be */
 140         apply_clip(cr);
 141         set_color(cr, color);
 142         cairo_move_to(cr, pos.left(), pos.top());
 143         pango_cairo_show_layout(cr, layout);
 144
 145         /* Cleanup */
 146         g_object_unref(layout);
 147         cairo_restore(cr);
 148 }