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 #define PANGO_ENABLE_ENGINE
  13
  14 #include <gtk/gtkversion.h>
  15 #include "Layout-TNG.h"
  16 #include "style.h"
  17 #include "svg/svg-length.h"
  18 #include "sp-object.h"
  19 #include "FontFactory.h"
  20
  21 namespace Inkscape {
  22 namespace Text {
  23
  24 void Layout::_clearInputObjects()
  25 {
  26     for(std::vector<InputStreamItem*>::iterator it = _input_stream.begin() ; it != _input_stream.end() ; it++)
  27         delete *it;
  28     _input_stream.clear();
  29     _input_wrap_shapes.clear();
  30 }
  31
  32 // this function does nothing more than store all its parameters for future reference
  33 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)
  34 {
  35     if (style == NULL) return;
  36
  37     InputStreamTextSource *new_source = new InputStreamTextSource;
  38
  39     new_source->source_cookie = source_cookie;
  40     new_source->text = &text;
  41     new_source->text_begin = text_begin;
  42     new_source->text_end = text_end;
  43     new_source->style = style;
  44     sp_style_ref(style);
  45
  46     new_source->text_length = 0;
  47     for ( ; text_begin != text_end && text_begin != text.end() ; text_begin++)
  48         new_source->text_length++;        // save this because calculating the length of a UTF-8 string is expensive
  49
  50     if (optional_attributes) {
  51         // we need to fill in x and y even if the text is empty so that empty paragraphs can be positioned correctly
  52         _copyInputVector(optional_attributes->x, optional_attributes_offset, &new_source->x, std::max(1, new_source->text_length));
  53         _copyInputVector(optional_attributes->y, optional_attributes_offset, &new_source->y, std::max(1, new_source->text_length));
  54         _copyInputVector(optional_attributes->dx, optional_attributes_offset, &new_source->dx, new_source->text_length);
  55         _copyInputVector(optional_attributes->dy, optional_attributes_offset, &new_source->dy, new_source->text_length);
  56         _copyInputVector(optional_attributes->rotate, optional_attributes_offset, &new_source->rotate, new_source->text_length);
  57         if (!optional_attributes->rotate.empty() && optional_attributes_offset >= optional_attributes->rotate.size()) {
  58             SVGLength last_rotate;
  59             last_rotate = 0.f;
  60             for (std::vector<SVGLength>::const_iterator it = optional_attributes->rotate.begin() ; it != optional_attributes->rotate.end() ; ++it)
  61                 if (it->_set)
  62                     last_rotate = *it;
  63             new_source->rotate.resize(1, last_rotate);
  64         }
  65     }
  66
  67     _input_stream.push_back(new_source);
  68 }
  69
  70 void Layout::_copyInputVector(std::vector<SVGLength> const &input_vector, unsigned input_offset, std::vector<SVGLength> *output_vector, size_t max_length)
  71 {
  72     output_vector->clear();
  73     if (input_offset >= input_vector.size()) return;
  74     output_vector->reserve(std::min(max_length, input_vector.size() - input_offset));
  75     while (input_offset < input_vector.size() && max_length != 0) {
  76         if (!input_vector[input_offset]._set)
  77             break;
  78         output_vector->push_back(input_vector[input_offset]);
  79         input_offset++;
  80         max_length--;
  81     }
  82 }
  83
  84 // just save what we've been given, really
  85 void Layout::appendControlCode(TextControlCode code, void *source_cookie, double width, double ascent, double descent)
  86 {
  87     InputStreamControlCode *new_code = new InputStreamControlCode;
  88
  89     new_code->source_cookie = source_cookie;
  90     new_code->code = code;
  91     new_code->width = width;
  92     new_code->ascent = ascent;
  93     new_code->descent = descent;
  94
  95     _input_stream.push_back(new_code);
  96 }
  97
  98 // more saving of the parameters
  99 void Layout::appendWrapShape(Shape const *shape, DisplayAlign display_align)
 100 {
 101     _input_wrap_shapes.push_back(InputWrapShape());
 102     _input_wrap_shapes.back().shape = shape;
 103     _input_wrap_shapes.back().display_align = display_align;
 104 }
 105
 106 int Layout::_enum_converter(int input, EnumConversionItem const *conversion_table, unsigned conversion_table_size)
 107 {
 108     for (unsigned i = 0 ; i < conversion_table_size ; i++)
 109         if (conversion_table[i].input == input)
 110             return conversion_table[i].output;
 111     return conversion_table[0].output;
 112 }
 113
 114 // ***** the style format interface
 115 // this doesn't include all accesses to SPStyle, only the ones that are non-trivial
 116
 117 static const float medium_font_size = 12.0;     // more of a default if all else fails than anything else
 118 float Layout::InputStreamTextSource::styleComputeFontSize() const
 119 {
 120     return style->font_size.computed;
 121
 122     // in case the computed value's not good enough, here's some manual code held in reserve:
 123     SPStyle const *this_style = style;
 124     float inherit_multiplier = 1.0;
 125
 126     for ( ; ; ) {
 127         if (this_style->font_size.set && !this_style->font_size.inherit) {
 128             switch (this_style->font_size.type) {
 129                 case SP_FONT_SIZE_LITERAL: {
 130                     switch(this_style->font_size.value) {   // these multipliers are straight out of the CSS spec
 131                             case SP_CSS_FONT_SIZE_XX_SMALL: return medium_font_size * inherit_multiplier * (3.0/5.0);
 132                             case SP_CSS_FONT_SIZE_X_SMALL:  return medium_font_size * inherit_multiplier * (3.0/4.0);
 133                             case SP_CSS_FONT_SIZE_SMALL:    return medium_font_size * inherit_multiplier * (8.0/9.0);
 134                         default:
 135                             case SP_CSS_FONT_SIZE_MEDIUM:   return medium_font_size * inherit_multiplier;
 136                             case SP_CSS_FONT_SIZE_LARGE:    return medium_font_size * inherit_multiplier * (6.0/5.0);
 137                             case SP_CSS_FONT_SIZE_X_LARGE:  return medium_font_size * inherit_multiplier * (3.0/2.0);
 138                             case SP_CSS_FONT_SIZE_XX_LARGE: return medium_font_size * inherit_multiplier * 2.0;
 139                             case SP_CSS_FONT_SIZE_SMALLER: inherit_multiplier *= 0.84; break;   //not exactly according to spec
 140                             case SP_CSS_FONT_SIZE_LARGER:  inherit_multiplier *= 1.26; break;   //not exactly according to spec
 141                     }
 142                     break;
 143                 }
 144                 case SP_FONT_SIZE_PERCENTAGE: {    // 'em' units should be in here, but aren't. Fix in style.cpp.
 145                     inherit_multiplier *= this_style->font_size.value;
 146                     break;
 147                 }
 148                 case SP_FONT_SIZE_LENGTH: {
 149                     return this_style->font_size.value * inherit_multiplier;
 150                 }
 151             }
 152         }
 153         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 154         this_style = this_style->object->parent->style;
 155         if (this_style == NULL) break;
 156     }
 157     return medium_font_size * inherit_multiplier;
 158 }
 159
 160 static const Layout::EnumConversionItem enum_convert_spstyle_block_progression_to_direction[] = {
 161     {SP_CSS_BLOCK_PROGRESSION_TB, Layout::TOP_TO_BOTTOM},
 162     {SP_CSS_BLOCK_PROGRESSION_LR, Layout::LEFT_TO_RIGHT},
 163     {SP_CSS_BLOCK_PROGRESSION_RL, Layout::RIGHT_TO_LEFT}};
 164
 165 static const Layout::EnumConversionItem enum_convert_spstyle_writing_mode_to_direction[] = {
 166     {SP_CSS_WRITING_MODE_LR_TB, Layout::TOP_TO_BOTTOM},
 167     {SP_CSS_WRITING_MODE_RL_TB, Layout::TOP_TO_BOTTOM},
 168     {SP_CSS_WRITING_MODE_TB_RL, Layout::RIGHT_TO_LEFT},
 169     {SP_CSS_WRITING_MODE_TB_LR, Layout::LEFT_TO_RIGHT}};
 170
 171 Layout::Direction Layout::InputStreamTextSource::styleGetBlockProgression() const
 172 {
 173     // this function shouldn't be necessary, but since style.cpp doesn't support
 174     // shorthand properties yet, it is.
 175     SPStyle const *this_style = style;
 176
 177     for ( ; ; ) {
 178         if (this_style->block_progression.set)
 179             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]));
 180         if (this_style->writing_mode.set)
 181             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]));
 182         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 183         this_style = this_style->object->parent->style;
 184         if (this_style == NULL) break;
 185     }
 186     return TOP_TO_BOTTOM;
 187
 188 }
 189
 190 static Layout::Alignment text_anchor_to_alignment(unsigned anchor, Layout::Direction /*para_direction*/)
 191 {
 192     switch (anchor) {
 193         default:
 194         case SP_CSS_TEXT_ANCHOR_START:  return Layout::LEFT;
 195         case SP_CSS_TEXT_ANCHOR_MIDDLE: return Layout::CENTER;
 196         case SP_CSS_TEXT_ANCHOR_END:    return Layout::RIGHT;
 197     }
 198 }
 199
 200 Layout::Alignment Layout::InputStreamTextSource::styleGetAlignment(Layout::Direction para_direction, bool try_text_align) const
 201 {
 202     if (!try_text_align)
 203         return text_anchor_to_alignment(style->text_anchor.computed, para_direction);
 204
 205     // there's no way to tell the difference between text-anchor set higher up the cascade to the default and
 206     // text-anchor never set anywhere in the cascade, so in order to detect which of text-anchor or text-align
 207     // to use we'll have to run up the style tree ourselves.
 208     SPStyle const *this_style = style;
 209
 210     for ( ; ; ) {
 211         // If both text-align and text-anchor are set at the same level, text-align takes
 212         // precedence because it is the most expressive.
 213         if (this_style->text_align.set) {
 214             switch (style->text_align.computed) {
 215                 default:
 216                 case SP_CSS_TEXT_ALIGN_START:   return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 217                 case SP_CSS_TEXT_ALIGN_END:     return para_direction == LEFT_TO_RIGHT ? RIGHT : LEFT;
 218                 case SP_CSS_TEXT_ALIGN_LEFT:    return LEFT;
 219                 case SP_CSS_TEXT_ALIGN_RIGHT:   return RIGHT;
 220                 case SP_CSS_TEXT_ALIGN_CENTER:  return CENTER;
 221                 case SP_CSS_TEXT_ALIGN_JUSTIFY: return FULL;
 222             }
 223         }
 224         if (this_style->text_anchor.set)
 225             return text_anchor_to_alignment(this_style->text_anchor.computed, para_direction);
 226         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 227         this_style = this_style->object->parent->style;
 228         if (this_style == NULL) break;
 229     }
 230     return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 231 }
 232
 233 static const Layout::EnumConversionItem enum_convert_spstyle_style_to_pango_style[] = {
 234     {SP_CSS_FONT_STYLE_NORMAL,  PANGO_STYLE_NORMAL},
 235     {SP_CSS_FONT_STYLE_ITALIC,  PANGO_STYLE_ITALIC},
 236     {SP_CSS_FONT_STYLE_OBLIQUE, PANGO_STYLE_OBLIQUE}};
 237
 238 static const Layout::EnumConversionItem enum_convert_spstyle_weight_to_pango_weight[] = {
 239     {SP_CSS_FONT_WEIGHT_NORMAL, PANGO_WEIGHT_NORMAL},
 240     {SP_CSS_FONT_WEIGHT_100, PANGO_WEIGHT_ULTRALIGHT},
 241     {SP_CSS_FONT_WEIGHT_200, PANGO_WEIGHT_ULTRALIGHT},
 242     {SP_CSS_FONT_WEIGHT_300, PANGO_WEIGHT_LIGHT},
 243     {SP_CSS_FONT_WEIGHT_400, PANGO_WEIGHT_NORMAL},
 244 #if GTK_CHECK_VERSION(2,6,0)
 245     {SP_CSS_FONT_WEIGHT_500, PANGO_WEIGHT_SEMIBOLD},
 246 #else
 247     {SP_CSS_FONT_WEIGHT_500, PANGO_WEIGHT_NORMAL},
 248 #endif
 249     {SP_CSS_FONT_WEIGHT_600, PANGO_WEIGHT_BOLD},
 250     {SP_CSS_FONT_WEIGHT_BOLD,PANGO_WEIGHT_BOLD},
 251     {SP_CSS_FONT_WEIGHT_700, PANGO_WEIGHT_BOLD},
 252     {SP_CSS_FONT_WEIGHT_800, PANGO_WEIGHT_ULTRABOLD},
 253     {SP_CSS_FONT_WEIGHT_900, PANGO_WEIGHT_HEAVY}};
 254
 255 static const Layout::EnumConversionItem enum_convert_spstyle_stretch_to_pango_stretch[] = {
 256     {SP_CSS_FONT_STRETCH_NORMAL,          PANGO_STRETCH_NORMAL},
 257     {SP_CSS_FONT_STRETCH_ULTRA_CONDENSED, PANGO_STRETCH_ULTRA_CONDENSED},
 258     {SP_CSS_FONT_STRETCH_EXTRA_CONDENSED, PANGO_STRETCH_EXTRA_CONDENSED},
 259     {SP_CSS_FONT_STRETCH_CONDENSED,       PANGO_STRETCH_CONDENSED},
 260     {SP_CSS_FONT_STRETCH_SEMI_CONDENSED,  PANGO_STRETCH_SEMI_CONDENSED},
 261     {SP_CSS_FONT_STRETCH_SEMI_EXPANDED,   PANGO_STRETCH_SEMI_EXPANDED},
 262     {SP_CSS_FONT_STRETCH_EXPANDED,        PANGO_STRETCH_EXPANDED},
 263     {SP_CSS_FONT_STRETCH_EXTRA_EXPANDED,  PANGO_STRETCH_EXTRA_EXPANDED},
 264     {SP_CSS_FONT_STRETCH_ULTRA_EXPANDED,  PANGO_STRETCH_ULTRA_EXPANDED}};
 265
 266 static const Layout::EnumConversionItem enum_convert_spstyle_variant_to_pango_variant[] = {
 267     {SP_CSS_FONT_VARIANT_NORMAL,     PANGO_VARIANT_NORMAL},
 268     {SP_CSS_FONT_VARIANT_SMALL_CAPS, PANGO_VARIANT_SMALL_CAPS}};
 269
 270 font_instance *Layout::InputStreamTextSource::styleGetFontInstance() const
 271 {
 272     PangoFontDescription *descr = styleGetFontDescription();
 273     if (descr == NULL) return NULL;
 274     font_instance *res = (font_factory::Default())->Face(descr);
 275     pango_font_description_free(descr);
 276     return res;
 277 }
 278
 279 PangoFontDescription *Layout::InputStreamTextSource::styleGetFontDescription() const
 280 {
 281     if (style->text == NULL) return NULL;
 282     PangoFontDescription *descr = pango_font_description_new();
 283     // Pango can't cope with spaces before or after the commas - let's remove them.
 284     // this code is not exactly unicode-safe, but it's similar to what's done in
 285     // pango, so it's not the limiting factor
 286     Glib::ustring family;
 287     if (style->text->font_family.value == NULL) {
 288         family = "Sans";
 289     } else {
 290         gchar **families = g_strsplit(style->text->font_family.value, ",", -1);
 291         if (families) {
 292             for (gchar **f = families ; *f ; ++f) {
 293                 g_strstrip(*f);
 294                 if (!family.empty()) family += ',';
 295                 family += *f;
 296             }
 297         }
 298         g_strfreev(families);
 299     }
 300
 301     pango_font_description_set_family(descr,family.c_str());
 302     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])));
 303     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])));
 304     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])));
 305 #ifdef USE_PANGO_WIN32
 306     // damn Pango fudges the size, so we need to unfudge. See source of pango_win32_font_map_init()
 307     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)
 308     // we don't set stretch on Win32, because pango-win32 has no concept of it
 309     // (Windows doesn't really provide any useful field it could use).
 310     // If we did set stretch, then any text with a font-stretch attribute would
 311     // end up falling back to Arial.
 312 #else
 313     pango_font_description_set_size(descr, (int) ((font_factory::Default())->fontSize*PANGO_SCALE)); // mandatory huge size (hinting workaround)
 314     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])));
 315 #endif
 316     return descr;
 317 }
 318
 319 Layout::InputStreamTextSource::~InputStreamTextSource()
 320 {
 321     sp_style_unref(style);
 322 }
 323
 324 }//namespace Text
 325 }//namespace Inkscape