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 "sp-string.h"
  20 #include "FontFactory.h"
  21
  22 #if !PANGO_VERSION_CHECK(1,24,0)
  23 #define PANGO_WEIGHT_THIN       static_cast<PangoWeight>(100)
  24 #define PANGO_WEIGHT_BOOK       static_cast<PangoWeight>(380)
  25 #define PANGO_WEIGHT_MEDIUM     static_cast<PangoWeight>(500)
  26 #define PANGO_WEIGHT_ULTRAHEAVY static_cast<PangoWeight>(1000)
  27 #endif
  28
  29 namespace Inkscape {
  30 namespace Text {
  31
  32 void Layout::_clearInputObjects()
  33 {
  34     for(std::vector<InputStreamItem*>::iterator it = _input_stream.begin() ; it != _input_stream.end() ; it++)
  35         delete *it;
  36     _input_stream.clear();
  37     _input_wrap_shapes.clear();
  38 }
  39
  40 // this function does nothing more than store all its parameters for future reference
  41 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)
  42 {
  43     if (style == NULL) return;
  44
  45     InputStreamTextSource *new_source = new InputStreamTextSource;
  46
  47     new_source->source_cookie = source_cookie;
  48     new_source->text = &text;
  49     new_source->text_begin = text_begin;
  50     new_source->text_end = text_end;
  51     new_source->style = style;
  52     sp_style_ref(style);
  53
  54     new_source->text_length = 0;
  55     for ( ; text_begin != text_end && text_begin != text.end() ; text_begin++)
  56         new_source->text_length++;        // save this because calculating the length of a UTF-8 string is expensive
  57
  58     if (optional_attributes) {
  59         // we need to fill in x and y even if the text is empty so that empty paragraphs can be positioned correctly
  60         _copyInputVector(optional_attributes->x, optional_attributes_offset, &new_source->x, std::max(1, new_source->text_length));
  61         _copyInputVector(optional_attributes->y, optional_attributes_offset, &new_source->y, std::max(1, new_source->text_length));
  62         _copyInputVector(optional_attributes->dx, optional_attributes_offset, &new_source->dx, new_source->text_length);
  63         _copyInputVector(optional_attributes->dy, optional_attributes_offset, &new_source->dy, new_source->text_length);
  64         _copyInputVector(optional_attributes->rotate, optional_attributes_offset, &new_source->rotate, new_source->text_length);
  65         if (!optional_attributes->rotate.empty() && optional_attributes_offset >= optional_attributes->rotate.size()) {
  66             SVGLength last_rotate;
  67             last_rotate = 0.f;
  68             for (std::vector<SVGLength>::const_iterator it = optional_attributes->rotate.begin() ; it != optional_attributes->rotate.end() ; ++it)
  69                 if (it->_set)
  70                     last_rotate = *it;
  71             new_source->rotate.resize(1, last_rotate);
  72         }
  73     }
  74
  75     _input_stream.push_back(new_source);
  76 }
  77
  78 void Layout::_copyInputVector(std::vector<SVGLength> const &input_vector, unsigned input_offset, std::vector<SVGLength> *output_vector, size_t max_length)
  79 {
  80     output_vector->clear();
  81     if (input_offset >= input_vector.size()) return;
  82     output_vector->reserve(std::min(max_length, input_vector.size() - input_offset));
  83     while (input_offset < input_vector.size() && max_length != 0) {
  84         if (!input_vector[input_offset]._set)
  85             break;
  86         output_vector->push_back(input_vector[input_offset]);
  87         input_offset++;
  88         max_length--;
  89     }
  90 }
  91
  92 // just save what we've been given, really
  93 void Layout::appendControlCode(TextControlCode code, void *source_cookie, double width, double ascent, double descent)
  94 {
  95     InputStreamControlCode *new_code = new InputStreamControlCode;
  96
  97     new_code->source_cookie = source_cookie;
  98     new_code->code = code;
  99     new_code->width = width;
 100     new_code->ascent = ascent;
 101     new_code->descent = descent;
 102
 103     _input_stream.push_back(new_code);
 104 }
 105
 106 // more saving of the parameters
 107 void Layout::appendWrapShape(Shape const *shape, DisplayAlign display_align)
 108 {
 109     _input_wrap_shapes.push_back(InputWrapShape());
 110     _input_wrap_shapes.back().shape = shape;
 111     _input_wrap_shapes.back().display_align = display_align;
 112 }
 113
 114 int Layout::_enum_converter(int input, EnumConversionItem const *conversion_table, unsigned conversion_table_size)
 115 {
 116     for (unsigned i = 0 ; i < conversion_table_size ; i++)
 117         if (conversion_table[i].input == input)
 118             return conversion_table[i].output;
 119     return conversion_table[0].output;
 120 }
 121
 122 // ***** the style format interface
 123 // this doesn't include all accesses to SPStyle, only the ones that are non-trivial
 124
 125 static const float medium_font_size = 12.0;     // more of a default if all else fails than anything else
 126 float Layout::InputStreamTextSource::styleComputeFontSize() const
 127 {
 128     return style->font_size.computed;
 129
 130     // in case the computed value's not good enough, here's some manual code held in reserve:
 131     SPStyle const *this_style = style;
 132     float inherit_multiplier = 1.0;
 133
 134     for ( ; ; ) {
 135         if (this_style->font_size.set && !this_style->font_size.inherit) {
 136             switch (this_style->font_size.type) {
 137                 case SP_FONT_SIZE_LITERAL: {
 138                     switch(this_style->font_size.value) {   // these multipliers are straight out of the CSS spec
 139                             case SP_CSS_FONT_SIZE_XX_SMALL: return medium_font_size * inherit_multiplier * (3.0/5.0);
 140                             case SP_CSS_FONT_SIZE_X_SMALL:  return medium_font_size * inherit_multiplier * (3.0/4.0);
 141                             case SP_CSS_FONT_SIZE_SMALL:    return medium_font_size * inherit_multiplier * (8.0/9.0);
 142                         default:
 143                             case SP_CSS_FONT_SIZE_MEDIUM:   return medium_font_size * inherit_multiplier;
 144                             case SP_CSS_FONT_SIZE_LARGE:    return medium_font_size * inherit_multiplier * (6.0/5.0);
 145                             case SP_CSS_FONT_SIZE_X_LARGE:  return medium_font_size * inherit_multiplier * (3.0/2.0);
 146                             case SP_CSS_FONT_SIZE_XX_LARGE: return medium_font_size * inherit_multiplier * 2.0;
 147                             case SP_CSS_FONT_SIZE_SMALLER: inherit_multiplier *= 0.84; break;   //not exactly according to spec
 148                             case SP_CSS_FONT_SIZE_LARGER:  inherit_multiplier *= 1.26; break;   //not exactly according to spec
 149                     }
 150                     break;
 151                 }
 152                 case SP_FONT_SIZE_PERCENTAGE: {    // 'em' units should be in here, but aren't. Fix in style.cpp.
 153                     inherit_multiplier *= this_style->font_size.value;
 154                     break;
 155                 }
 156                 case SP_FONT_SIZE_LENGTH: {
 157                     return this_style->font_size.value * inherit_multiplier;
 158                 }
 159             }
 160         }
 161         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 162         this_style = this_style->object->parent->style;
 163         if (this_style == NULL) break;
 164     }
 165     return medium_font_size * inherit_multiplier;
 166 }
 167
 168 static const Layout::EnumConversionItem enum_convert_spstyle_block_progression_to_direction[] = {
 169     {SP_CSS_BLOCK_PROGRESSION_TB, Layout::TOP_TO_BOTTOM},
 170     {SP_CSS_BLOCK_PROGRESSION_LR, Layout::LEFT_TO_RIGHT},
 171     {SP_CSS_BLOCK_PROGRESSION_RL, Layout::RIGHT_TO_LEFT}};
 172
 173 static const Layout::EnumConversionItem enum_convert_spstyle_writing_mode_to_direction[] = {
 174     {SP_CSS_WRITING_MODE_LR_TB, Layout::TOP_TO_BOTTOM},
 175     {SP_CSS_WRITING_MODE_RL_TB, Layout::TOP_TO_BOTTOM},
 176     {SP_CSS_WRITING_MODE_TB_RL, Layout::RIGHT_TO_LEFT},
 177     {SP_CSS_WRITING_MODE_TB_LR, Layout::LEFT_TO_RIGHT}};
 178
 179 Layout::Direction Layout::InputStreamTextSource::styleGetBlockProgression() const
 180 {
 181     // this function shouldn't be necessary, but since style.cpp doesn't support
 182     // shorthand properties yet, it is.
 183     SPStyle const *this_style = style;
 184
 185     for ( ; ; ) {
 186         if (this_style->block_progression.set)
 187             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]));
 188         if (this_style->writing_mode.set)
 189             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]));
 190         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 191         this_style = this_style->object->parent->style;
 192         if (this_style == NULL) break;
 193     }
 194     return TOP_TO_BOTTOM;
 195
 196 }
 197
 198 static Layout::Alignment text_anchor_to_alignment(unsigned anchor, Layout::Direction /*para_direction*/)
 199 {
 200     switch (anchor) {
 201         default:
 202         case SP_CSS_TEXT_ANCHOR_START:  return Layout::LEFT;
 203         case SP_CSS_TEXT_ANCHOR_MIDDLE: return Layout::CENTER;
 204         case SP_CSS_TEXT_ANCHOR_END:    return Layout::RIGHT;
 205     }
 206 }
 207
 208 Layout::Alignment Layout::InputStreamTextSource::styleGetAlignment(Layout::Direction para_direction, bool try_text_align) const
 209 {
 210     if (!try_text_align)
 211         return text_anchor_to_alignment(style->text_anchor.computed, para_direction);
 212
 213     // there's no way to tell the difference between text-anchor set higher up the cascade to the default and
 214     // text-anchor never set anywhere in the cascade, so in order to detect which of text-anchor or text-align
 215     // to use we'll have to run up the style tree ourselves.
 216     SPStyle const *this_style = style;
 217
 218     for ( ; ; ) {
 219         // If both text-align and text-anchor are set at the same level, text-align takes
 220         // precedence because it is the most expressive.
 221         if (this_style->text_align.set) {
 222             switch (style->text_align.computed) {
 223                 default:
 224                 case SP_CSS_TEXT_ALIGN_START:   return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 225                 case SP_CSS_TEXT_ALIGN_END:     return para_direction == LEFT_TO_RIGHT ? RIGHT : LEFT;
 226                 case SP_CSS_TEXT_ALIGN_LEFT:    return LEFT;
 227                 case SP_CSS_TEXT_ALIGN_RIGHT:   return RIGHT;
 228                 case SP_CSS_TEXT_ALIGN_CENTER:  return CENTER;
 229                 case SP_CSS_TEXT_ALIGN_JUSTIFY: return FULL;
 230             }
 231         }
 232         if (this_style->text_anchor.set)
 233             return text_anchor_to_alignment(this_style->text_anchor.computed, para_direction);
 234         if (this_style->object == NULL || this_style->object->parent == NULL) break;
 235         this_style = this_style->object->parent->style;
 236         if (this_style == NULL) break;
 237     }
 238     return para_direction == LEFT_TO_RIGHT ? LEFT : RIGHT;
 239 }
 240
 241 static const Layout::EnumConversionItem enum_convert_spstyle_style_to_pango_style[] = {
 242     {SP_CSS_FONT_STYLE_NORMAL,  PANGO_STYLE_NORMAL},
 243     {SP_CSS_FONT_STYLE_ITALIC,  PANGO_STYLE_ITALIC},
 244     {SP_CSS_FONT_STYLE_OBLIQUE, PANGO_STYLE_OBLIQUE}};
 245
 246 static const Layout::EnumConversionItem enum_convert_spstyle_weight_to_pango_weight[] = {
 247   // NB: The Pango web page calls 500 "the normal font" but both CSS2 and the Pango
 248   // enumeration define 400 as normal.
 249     {SP_CSS_FONT_WEIGHT_NORMAL, PANGO_WEIGHT_NORMAL},
 250     {SP_CSS_FONT_WEIGHT_BOLD,PANGO_WEIGHT_BOLD},
 251     {SP_CSS_FONT_WEIGHT_100, PANGO_WEIGHT_THIN},
 252     {SP_CSS_FONT_WEIGHT_200, PANGO_WEIGHT_ULTRALIGHT},
 253     {SP_CSS_FONT_WEIGHT_300, PANGO_WEIGHT_LIGHT},
 254     {SP_CSS_FONT_WEIGHT_400, PANGO_WEIGHT_NORMAL},
 255     {SP_CSS_FONT_WEIGHT_500, PANGO_WEIGHT_MEDIUM},
 256     {SP_CSS_FONT_WEIGHT_600, PANGO_WEIGHT_SEMIBOLD},
 257     {SP_CSS_FONT_WEIGHT_700, PANGO_WEIGHT_BOLD},
 258     {SP_CSS_FONT_WEIGHT_800, PANGO_WEIGHT_ULTRABOLD},
 259     {SP_CSS_FONT_WEIGHT_900, PANGO_WEIGHT_HEAVY}};
 260
 261 static const Layout::EnumConversionItem enum_convert_spstyle_stretch_to_pango_stretch[] = {
 262     {SP_CSS_FONT_STRETCH_NORMAL,          PANGO_STRETCH_NORMAL},
 263     {SP_CSS_FONT_STRETCH_ULTRA_CONDENSED, PANGO_STRETCH_ULTRA_CONDENSED},
 264     {SP_CSS_FONT_STRETCH_EXTRA_CONDENSED, PANGO_STRETCH_EXTRA_CONDENSED},
 265     {SP_CSS_FONT_STRETCH_CONDENSED,       PANGO_STRETCH_CONDENSED},
 266     {SP_CSS_FONT_STRETCH_SEMI_CONDENSED,  PANGO_STRETCH_SEMI_CONDENSED},
 267     {SP_CSS_FONT_STRETCH_SEMI_EXPANDED,   PANGO_STRETCH_SEMI_EXPANDED},
 268     {SP_CSS_FONT_STRETCH_EXPANDED,        PANGO_STRETCH_EXPANDED},
 269     {SP_CSS_FONT_STRETCH_EXTRA_EXPANDED,  PANGO_STRETCH_EXTRA_EXPANDED},
 270     {SP_CSS_FONT_STRETCH_ULTRA_EXPANDED,  PANGO_STRETCH_ULTRA_EXPANDED}};
 271
 272 static const Layout::EnumConversionItem enum_convert_spstyle_variant_to_pango_variant[] = {
 273     {SP_CSS_FONT_VARIANT_NORMAL,     PANGO_VARIANT_NORMAL},
 274     {SP_CSS_FONT_VARIANT_SMALL_CAPS, PANGO_VARIANT_SMALL_CAPS}};
 275
 276 font_instance *Layout::InputStreamTextSource::styleGetFontInstance() const
 277 {
 278     PangoFontDescription *descr = styleGetFontDescription();
 279     if (descr == NULL) return NULL;
 280     font_instance *res = (font_factory::Default())->Face(descr);
 281     pango_font_description_free(descr);
 282     return res;
 283 }
 284
 285 PangoFontDescription *Layout::InputStreamTextSource::styleGetFontDescription() const
 286 {
 287     if (style->text == NULL) return NULL;
 288     PangoFontDescription *descr = pango_font_description_new();
 289     // Pango can't cope with spaces before or after the commas - let's remove them.
 290     // this code is not exactly unicode-safe, but it's similar to what's done in
 291     // pango, so it's not the limiting factor
 292     Glib::ustring family;
 293     if (style->text->font_family.value == NULL) {
 294         family = "Sans";
 295     } else {
 296         gchar **families = g_strsplit(style->text->font_family.value, ",", -1);
 297         if (families) {
 298             for (gchar **f = families ; *f ; ++f) {
 299                 g_strstrip(*f);
 300                 if (!family.empty()) family += ',';
 301                 family += *f;
 302             }
 303         }
 304         g_strfreev(families);
 305     }
 306
 307     pango_font_description_set_family(descr,family.c_str());
 308     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])));
 309     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])));
 310     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])));
 311 #ifdef USE_PANGO_WIN32
 312     // damn Pango fudges the size, so we need to unfudge. See source of pango_win32_font_map_init()
 313     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)
 314     // we don't set stretch on Win32, because pango-win32 has no concept of it
 315     // (Windows doesn't really provide any useful field it could use).
 316     // If we did set stretch, then any text with a font-stretch attribute would
 317     // end up falling back to Arial.
 318 #else
 319     pango_font_description_set_size(descr, (int) ((font_factory::Default())->fontSize*PANGO_SCALE)); // mandatory huge size (hinting workaround)
 320     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])));
 321 #endif
 322     return descr;
 323 }
 324
 325 Layout::InputStreamTextSource::~InputStreamTextSource()
 326 {
 327     sp_style_unref(style);
 328 }
 329
 330 }//namespace Text
 331 }//namespace Inkscape