src/libnrtype/Layout-TNG-Input.cpp

   1 /*
   2  * Inkscape::Text::Layout - text layout engine input functions
   3  *
   4  * Authors:
   5  *   Richard Hughes <cyreve@users.sf.net>
   6  *
   7  * Copyright (C) 2005 Richard Hughes
   8  *
   9  * Released under GNU GPL, read the file 'COPYING' for more information
  10  */
  11
  12 #include <gtk/gtkversion.h>
  13 #include "Layout-TNG.h"
  14 #include "style.h"
  15 #include "svg/svg-length.h"
  16 #include "sp-object.h"
  17 #include "FontFactory.h"
  18
  19 namespace Inkscape {
  20 namespace Text {
  21
  22 void Layout::_clearInputObjects()
  23 {
  24     for(std::vector<InputStreamItem*>::iterator it = _input_stream.begin() ; it != _input_stream.end() ; it++)
  25         delete *it;
  26     _input_stream.clear();
  27     _input_wrap_shapes.clear();
  28 }
  29
  30 // this function does nothing more than store all its parameters for future reference
  31 void Layout::appendText(Glib::ustring const &text, SPStyle *style, void *source_cookie, OptionalTextTagAttrs const *optional_attributes, unsigned optional_attributes_offset, Glib::ustring::const_iterator text_begin, Glib::ustring::const_iterator text_end)
  32 {
  33     if (style == NULL) return;
  34
  35     InputStreamTextSource *new_source = new InputStreamTextSource;
  36
  37     new_source->source_cookie = source_cookie;
  38     new_source->text = &text;
  39     new_source->text_begin = text_begin;
  40     new_source->text_end = text_end;
  41     new_source->style = style;
  42     sp_style_ref(style);
  43
  44     new_source->text_length = 0;
  45     for ( ; text_begin != text_end && text_begin != text.end() ; text_begin++)
  46         new_source->text_length++;        // save this because calculating the length of a UTF-8 string is expensive
  47
  48     if (optional_attributes) {
  49         // we need to fill in x and y even if the text is empty so that empty paragraphs can be positioned correctly
  50         _copyInputVector(optional_attributes->x, optional_attributes_offset, &new_source->x, std::max(1, new_source->text_length));
  51         _copyInputVector(optional_attributes->y, optional_attributes_offset, &new_source->y, std::max(1, new_source->text_length));
  52         _copyInputVector(optional_attributes->dx, optional_attributes_offset, &new_source->dx, new_source->text_length);
  53         _copyInputVector(optional_attributes->dy, optional_attributes_offset, &new_source->dy, new_source->text_length);
  54         _copyInputVector(optional_attributes->rotate, optional_attributes_offset, &new_source->rotate, new_source->text_length);
  55     }
  56
  57     _input_stream.push_back(new_source);
  58 }
  59
  60 void Layout::_copyInputVector(std::vector<SVGLength> const &input_vector, unsigned input_offset, std::vector<SVGLength> *output_vector, size_t max_length)
  61 {
  62     output_vector->clear();
  63     if (input_offset >= input_vector.size()) return;
  64     output_vector->reserve(std::min(max_length, input_vector.size() - input_offset));
  65     while (input_offset < input_vector.size() && max_length != 0) {
  66         if (!input_vector[input_offset]._set)
  67             break;
  68         output_vector->push_back(input_vector[input_offset]);
  69         input_offset++;
  70         max_length--;
  71     }
  72 }
  73
  74 // just save what we've been given, really
  75 void Layout::appendControlCode(TextControlCode code, void *source_cookie, double width, double ascent, double descent)
  76 {
  77     InputStreamControlCode *new_code = new InputStreamControlCode;
  78
  79     new_code->source_cookie = source_cookie;
  80     new_code->code = code;
  81     new_code->width = width;
  82     new_code->ascent = ascent;
  83     new_code->descent = descent;
  84
  85     _input_stream.push_back(new_code);
  86 }
  87
  88 // more saving of the parameters
  89 void Layout::appendWrapShape(Shape const *shape, DisplayAlign display_align)
  90 {
  91     _input_wrap_shapes.push_back(InputWrapShape());
  92     _input_wrap_shapes.back().shape = shape;
  93     _input_wrap_shapes.back().display_align = display_align;
  94 }
  95
  96 int Layout::_enum_converter(int input, EnumConversionItem const *conversion_table, unsigned conversion_table_size)
  97 {
  98     for (unsigned i = 0 ; i < conversion_table_size ; i++)
  99         if (conversion_table[i].input == input)
 100             return conversion_table[i].output;
 101     return conversion_table[0].output;
 102 }
 103
 104 // ***** the style format interface
 105 // this doesn't include all accesses to SPStyle, only the ones that are non-trivial
 106
 107 static const float medium_font_size = 12.0;     // more of a default if all else fails than anything else
 108 float Layout::InputStreamTextSource::styleComputeFontSize() const
 109 {
 110     return style->font_size.computed;
 111
 112     // in case the computed value's not good enough, here's some manual code held in reserve:
 113     SPStyle const *this_style = style;
 114     float inherit_multiplier = 1.0;
 115
 116     for ( ; ; ) {
 117         if (this_style->font_size.set && !this_style->font_size.inherit) {
 118             switch (this_style->font_size.type) {
 119                 case SP_FONT_SIZE_LITERAL: {
 120                     switch(this_style->font_size.value) {   // these multipliers are straight out of the CSS spec
 121                             case SP_CSS_FONT_SIZE_XX_SMALL: return medium_font_size * inherit_multiplier * (3.0/5.0);
 122                             case SP_CSS_FONT_SIZE_X_SMALL:  return medium_font_size * inherit_multiplier * (3.0/4.0);
 123                             case SP_CSS_FONT_SIZE_SMALL:    return medium_font_size * inherit_multiplier * (8.0/9.0);
 124                         default:
 125                             case SP_CSS_FONT_SIZE_MEDIUM:   return medium_font_size * inherit_multiplier;
 126                             case SP_CSS_FONT_SIZE_LARGE:    return medium_font_size * inherit_multiplier * (6.0/5.0);
 127                             case SP_CSS_FONT_SIZE_X_LARGE:  return medium_font_size * inherit_multiplier * (3.0/2.0);
 128                             case SP_CSS_FONT_SIZE_XX_LARGE: return medium_font_size * inherit_multiplier * 2.0;
 129                             case SP_CSS_FONT_SIZE_SMALLER: inherit_multiplier *= 0.84; break;   //not exactly according to spec
 130                             case SP_CSS_FONT_SIZE_LARGER:  inherit_multiplier *= 1.26; break;   //not exactly according to spec
 131                     }
 132                     break;
 133                 }
 134                 case SP_FONT_SIZE_PERCENTAGE: {    // 'em' units should be in here, but aren't. Fix in style.cpp.
 135                     inherit_multiplier *= this_style->font_size.value;
 136                     break;
 137                 }
 138                 case SP_FONT_SIZE_LENGTH: {
 139                     return this_style->font_size.value * inherit_multiplier;
 140                 }
 141             }
 142         }
 143         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 144         this_style = this_style->object->parent->style;
 145         if (this_style == NULL) break;
 146     }
 147     return medium_font_size * inherit_multiplier;
 148 }
 149
 150 static const Layout::EnumConversionItem enum_convert_spstyle_block_progression_to_direction[] = {
 151     {SP_CSS_BLOCK_PROGRESSION_TB, Layout::TOP_TO_BOTTOM},
 152     {SP_CSS_BLOCK_PROGRESSION_LR, Layout::LEFT_TO_RIGHT},
 153     {SP_CSS_BLOCK_PROGRESSION_RL, Layout::RIGHT_TO_LEFT}};
 154
 155 static const Layout::EnumConversionItem enum_convert_spstyle_writing_mode_to_direction[] = {
 156     {SP_CSS_WRITING_MODE_LR_TB, Layout::TOP_TO_BOTTOM},
 157     {SP_CSS_WRITING_MODE_RL_TB, Layout::TOP_TO_BOTTOM},
 158     {SP_CSS_WRITING_MODE_TB_RL, Layout::RIGHT_TO_LEFT},
 159     {SP_CSS_WRITING_MODE_TB_LR, Layout::LEFT_TO_RIGHT}};
 160
 161 Layout::Direction Layout::InputStreamTextSource::styleGetBlockProgression() const
 162 {
 163     // this function shouldn't be necessary, but since style.cpp doesn't support
 164     // shorthand properties yet, it is.
 165     SPStyle const *this_style = style;
 166
 167     for ( ; ; ) {
 168         if (this_style->block_progression.set)
 169             return (Layout::Direction)_enum_converter(this_style->block_progression.computed, enum_convert_spstyle_block_progression_to_direction, sizeof(enum_convert_spstyle_block_progression_to_direction)/sizeof(enum_convert_spstyle_block_progression_to_direction[0]));
 170         if (this_style->writing_mode.set)
 171             return (Layout::Direction)_enum_converter(this_style->writing_mode.computed, enum_convert_spstyle_writing_mode_to_direction, sizeof(enum_convert_spstyle_writing_mode_to_direction)/sizeof(enum_convert_spstyle_writing_mode_to_direction[0]));
 172         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 173         this_style = this_style->object->parent->style;
 174         if (this_style == NULL) break;
 175     }
 176     return TOP_TO_BOTTOM;
 177
 178 }
 179
 180 static Layout::Alignment text_anchor_to_alignment(unsigned anchor, Layout::Direction /*para_direction*/)
 181 {
 182     switch (anchor) {
 183         default:
 184         case SP_CSS_TEXT_ANCHOR_START:  return Layout::LEFT;
 185         case SP_CSS_TEXT_ANCHOR_MIDDLE: return Layout::CENTER;
 186         case SP_CSS_TEXT_ANCHOR_END:    return Layout::RIGHT;
 187     }
 188 }
 189
 190 Layout::Alignment Layout::InputStreamTextSource::styleGetAlignment(Layout::Direction para_direction, bool try_text_align) const
 191 {
 192     if (!try_text_align)
 193         return text_anchor_to_alignment(style->text_anchor.computed, para_direction);
 194
 195     // there's no way to tell the difference between text-anchor set higher up the cascade to the default and
 196     // text-anchor never set anywhere in the cascade, so in order to detect which of text-anchor or text-align
 197     // to use we'll have to run up the style tree ourselves.
 198     SPStyle const *this_style = style;
 199
 200     for ( ; ; ) {
 201         // If both text-align and text-anchor are set at the same level, text-align takes
 202         // precedence because it is the most expressive.
 203         if (this_style->text_align.set) {
 204             switch (style->text_align.computed) {
 205                 default:
 206                 case SP_CSS_TEXT_ALIGN_START:   return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 207                 case SP_CSS_TEXT_ALIGN_END:     return para_direction == LEFT_TO_RIGHT ? RIGHT : LEFT;
 208                 case SP_CSS_TEXT_ALIGN_LEFT:    return LEFT;
 209                 case SP_CSS_TEXT_ALIGN_RIGHT:   return RIGHT;
 210                 case SP_CSS_TEXT_ALIGN_CENTER:  return CENTER;
 211                 case SP_CSS_TEXT_ALIGN_JUSTIFY: return FULL;
 212             }
 213         }
 214         if (this_style->text_anchor.set)
 215             return text_anchor_to_alignment(this_style->text_anchor.computed, para_direction);
 216         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 217         this_style = this_style->object->parent->style;
 218         if (this_style == NULL) break;
 219     }
 220     return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 221 }
 222
 223 static const Layout::EnumConversionItem enum_convert_spstyle_style_to_pango_style[] = {
 224     {SP_CSS_FONT_STYLE_NORMAL,  PANGO_STYLE_NORMAL},
 225     {SP_CSS_FONT_STYLE_ITALIC,  PANGO_STYLE_ITALIC},
 226     {SP_CSS_FONT_STYLE_OBLIQUE, PANGO_STYLE_OBLIQUE}};
 227
 228 static const Layout::EnumConversionItem enum_convert_spstyle_weight_to_pango_weight[] = {
 229     {SP_CSS_FONT_WEIGHT_NORMAL, PANGO_WEIGHT_NORMAL},
 230     {SP_CSS_FONT_WEIGHT_100, PANGO_WEIGHT_ULTRALIGHT},
 231     {SP_CSS_FONT_WEIGHT_200, PANGO_WEIGHT_ULTRALIGHT},
 232     {SP_CSS_FONT_WEIGHT_300, PANGO_WEIGHT_LIGHT},
 233     {SP_CSS_FONT_WEIGHT_400, PANGO_WEIGHT_NORMAL},
 234 #if GTK_CHECK_VERSION(2,6,0)
 235     {SP_CSS_FONT_WEIGHT_500, PANGO_WEIGHT_SEMIBOLD},
 236 #else
 237     {SP_CSS_FONT_WEIGHT_500, PANGO_WEIGHT_NORMAL},
 238 #endif
 239     {SP_CSS_FONT_WEIGHT_600, PANGO_WEIGHT_BOLD},
 240     {SP_CSS_FONT_WEIGHT_BOLD,PANGO_WEIGHT_BOLD},
 241     {SP_CSS_FONT_WEIGHT_700, PANGO_WEIGHT_BOLD},
 242     {SP_CSS_FONT_WEIGHT_800, PANGO_WEIGHT_ULTRABOLD},
 243     {SP_CSS_FONT_WEIGHT_900, PANGO_WEIGHT_HEAVY}};
 244
 245 static const Layout::EnumConversionItem enum_convert_spstyle_stretch_to_pango_stretch[] = {
 246     {SP_CSS_FONT_STRETCH_NORMAL,          PANGO_STRETCH_NORMAL},
 247     {SP_CSS_FONT_STRETCH_ULTRA_CONDENSED, PANGO_STRETCH_ULTRA_CONDENSED},
 248     {SP_CSS_FONT_STRETCH_EXTRA_CONDENSED, PANGO_STRETCH_EXTRA_CONDENSED},
 249     {SP_CSS_FONT_STRETCH_CONDENSED,       PANGO_STRETCH_CONDENSED},
 250     {SP_CSS_FONT_STRETCH_SEMI_CONDENSED,  PANGO_STRETCH_SEMI_CONDENSED},
 251     {SP_CSS_FONT_STRETCH_SEMI_EXPANDED,   PANGO_STRETCH_SEMI_EXPANDED},
 252     {SP_CSS_FONT_STRETCH_EXPANDED,        PANGO_STRETCH_EXPANDED},
 253     {SP_CSS_FONT_STRETCH_EXTRA_EXPANDED,  PANGO_STRETCH_EXTRA_EXPANDED},
 254     {SP_CSS_FONT_STRETCH_ULTRA_EXPANDED,  PANGO_STRETCH_ULTRA_EXPANDED}};
 255
 256 static const Layout::EnumConversionItem enum_convert_spstyle_variant_to_pango_variant[] = {
 257     {SP_CSS_FONT_VARIANT_NORMAL,     PANGO_VARIANT_NORMAL},
 258     {SP_CSS_FONT_VARIANT_SMALL_CAPS, PANGO_VARIANT_SMALL_CAPS}};
 259
 260 font_instance *Layout::InputStreamTextSource::styleGetFontInstance() const
 261 {
 262     PangoFontDescription *descr = styleGetFontDescription();
 263     if (descr == NULL) return NULL;
 264     font_instance *res = (font_factory::Default())->Face(descr);
 265     pango_font_description_free(descr);
 266     return res;
 267 }
 268
 269 PangoFontDescription *Layout::InputStreamTextSource::styleGetFontDescription() const
 270 {
 271     if (style->text == NULL) return NULL;
 272     PangoFontDescription *descr = pango_font_description_new();
 273     // Pango can't cope with spaces before or after the commas - let's remove them.
 274     // this code is not exactly unicode-safe, but it's similar to what's done in
 275     // pango, so it's not the limiting factor
 276     Glib::ustring family;
 277     if (style->text->font_family.value == NULL) {
 278         family = "Sans";
 279     } else {
 280         gchar **families = g_strsplit(style->text->font_family.value, ",", -1);
 281         if (families) {
 282             for (gchar **f = families ; *f ; ++f) {
 283                 g_strstrip(*f);
 284                 if (!family.empty()) family += ',';
 285                 family += *f;
 286             }
 287         }
 288         g_strfreev(families);
 289     }
 290
 291     pango_font_description_set_family(descr,family.c_str());
 292     pango_font_description_set_weight(descr,(PangoWeight)_enum_converter(style->font_weight.computed,  enum_convert_spstyle_weight_to_pango_weight,   sizeof(enum_convert_spstyle_weight_to_pango_weight)/sizeof(enum_convert_spstyle_weight_to_pango_weight[0])));
 293     pango_font_description_set_style(descr,(PangoStyle)_enum_converter(style->font_style.computed,   enum_convert_spstyle_style_to_pango_style,     sizeof(enum_convert_spstyle_style_to_pango_style)/sizeof(enum_convert_spstyle_style_to_pango_style[0])));
 294     pango_font_description_set_variant(descr,(PangoVariant)_enum_converter(style->font_variant.computed, enum_convert_spstyle_variant_to_pango_variant, sizeof(enum_convert_spstyle_variant_to_pango_variant)/sizeof(enum_convert_spstyle_variant_to_pango_variant[0])));
 295 #ifdef USE_PANGO_WIN32
 296     // damn Pango fudges the size, so we need to unfudge. See source of pango_win32_font_map_init()
 297     pango_font_description_set_size(descr, (int) ((font_factory::Default())->fontSize*PANGO_SCALE*72/GetDeviceCaps(pango_win32_get_dc(),LOGPIXELSY))); // mandatory huge size (hinting workaround)
 298     // we don't set stretch on Win32, because pango-win32 has no concept of it
 299     // (Windows doesn't really provide any useful field it could use).
 300     // If we did set stretch, then any text with a font-stretch attribute would
 301     // end up falling back to Arial.
 302 #else
 303     pango_font_description_set_size(descr, (int) ((font_factory::Default())->fontSize*PANGO_SCALE)); // mandatory huge size (hinting workaround)
 304     pango_font_description_set_stretch(descr,(PangoStretch)_enum_converter(style->font_stretch.computed, enum_convert_spstyle_stretch_to_pango_stretch, sizeof(enum_convert_spstyle_stretch_to_pango_stretch)/sizeof(enum_convert_spstyle_stretch_to_pango_stretch[0])));
 305 #endif
 306     return descr;
 307 }
 308
 309 Layout::InputStreamTextSource::~InputStreamTextSource()
 310 {
 311     sp_style_unref(style);
 312 }
 313
 314 }//namespace Text
 315 }//namespace Inkscape