libRocket/Source/Core/BitmapFont/FontFaceHandle.cpp

/*
 * This source file is part of libRocket, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://www.librocket.com
 *
 * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 */

#include "../precompiled.h"
#include "FontFaceHandle.h"
#include "FontFaceLayer.h"
#include <algorithm>
#include "../TextureLayout.h"

namespace Rocket {
namespace Core {
namespace BitmapFont {

class FontEffectSort
{
public:
    bool operator()(const Rocket::Core::FontEffect* lhs, const Rocket::Core::FontEffect* rhs)
    {
        return lhs->GetZIndex() < rhs->GetZIndex();
    }
};

FontFaceHandle::FontFaceHandle()
{
    size = 0;
    average_advance = 0;
    x_height = 0;
    line_height = 0;
    baseline = 0;

    underline_position = 0;
    underline_thickness = 0;

    base_layer = NULL;
}

FontFaceHandle::~FontFaceHandle()
{
}

// Initialises the handle so it is able to render text.
bool FontFaceHandle::Initialise(BitmapFontDefinitions *bm_face, const String& _charset, int _size)
{
    this->bm_face = bm_face;
    size = _size;
    TextureWidth = bm_face->CommonCharactersInfo.ScaleWidth;
    TextureHeight = bm_face->CommonCharactersInfo.ScaleHeight;
    raw_charset = _charset;

    // Construct proper path to texture
    URL fnt_source = bm_face->Face.Source;
    URL bitmap_source = bm_face->Face.BitmapSource;
    if(bitmap_source.GetPath().Empty())
    {
        TextureSource = fnt_source.GetPath() + bitmap_source.GetFileName();
        if(!bitmap_source.GetExtension().Empty())
        {
            TextureSource += "." + bitmap_source.GetExtension();
        }
    }
    else
    {
        TextureSource = bitmap_source.GetPathedFileName();
    }

    if (!UnicodeRange::BuildList(charset, raw_charset))
    {
        Log::Message(Log::LT_ERROR, "Invalid font charset '%s'.", raw_charset.CString());
        return false;
    }

    // Construct the list of the characters specified by the charset.
    for (size_t i = 0; i < charset.size(); ++i)
        BuildGlyphMap(bm_face, charset[i]);

    // Generate the metrics for the handle.
    GenerateMetrics(bm_face);

    // Generate the default layer and layer configuration.
    base_layer = GenerateLayer(NULL);
    layer_configurations.push_back(LayerConfiguration());
    layer_configurations.back().push_back(base_layer);

    return true;
}

// Returns the width a string will take up if rendered with this handle.
int FontFaceHandle::GetStringWidth(const WString& string, word prior_character) const
{
    int width = 0;

    for (size_t i = 0; i < string.Length(); i++)
    {
        word character_code = string[i];

        if (character_code >= glyphs.size())
            continue;
        const FontGlyph &glyph = glyphs[character_code];

        // Adjust the cursor for the kerning between this character and the previous one.
        if (prior_character != 0)
            width += GetKerning(prior_character, string[i]);
        // Adjust the cursor for this character's advance.
        width += glyph.advance;

        prior_character = character_code;
    }

    return width;
}

// Generates, if required, the layer configuration for a given array of font effects.
int FontFaceHandle::GenerateLayerConfiguration(FontEffectMap& font_effects)
{
    if (font_effects.empty())
        return 0;

    // Prepare a list of effects, sorted by z-index.
    FontEffectList sorted_effects;
    for (FontEffectMap::const_iterator i = font_effects.begin(); i != font_effects.end(); ++i)
        sorted_effects.push_back(i->second);

    std::sort(sorted_effects.begin(), sorted_effects.end(), FontEffectSort());

    // Check each existing configuration for a match with this arrangement of effects.
    int configuration_index = 1;
    for (; configuration_index < (int) layer_configurations.size(); ++configuration_index)
    {
        const LayerConfiguration& configuration = layer_configurations[configuration_index];

        // Check the size is correct. For a math, there should be one layer in the configuration
        // plus an extra for the base layer.
        if (configuration.size() != sorted_effects.size() + 1)
            continue;

        // Check through each layer, checking it was created by the same effect as the one we're
        // checking.
        size_t effect_index = 0;
        for (size_t i = 0; i < configuration.size(); ++i)
        {
            // Skip the base layer ...
            if (configuration[i]->GetFontEffect() == NULL)
                continue;

            // If the ith layer's effect doesn't match the equivalent effect, then this
            // configuration can't match.
            if (configuration[i]->GetFontEffect() != sorted_effects[effect_index])
                break;

            // Check the next one ...
            ++effect_index;
        }

        if (effect_index == sorted_effects.size())
            return configuration_index;
    }

    // No match, so we have to generate a new layer configuration.
    layer_configurations.push_back(LayerConfiguration());
    LayerConfiguration& layer_configuration = layer_configurations.back();

    bool added_base_layer = false;

    for (size_t i = 0; i < sorted_effects.size(); ++i)
    {
        if (!added_base_layer &&
            sorted_effects[i]->GetZIndex() >= 0)
        {
            layer_configuration.push_back(base_layer);
            added_base_layer = true;
        }

        layer_configuration.push_back(GenerateLayer(sorted_effects[i]));
    }

    // Add the base layer now if we still haven't added it.
    if (!added_base_layer)
        layer_configuration.push_back(base_layer);

    return (int) (layer_configurations.size() - 1);
}

// Generates the texture data for a layer (for the texture database).
bool FontFaceHandle::GenerateLayerTexture(const byte*& texture_data, Vector2i& texture_dimensions, Rocket::Core::FontEffect* layer_id, int texture_id)
{
    FontLayerMap::iterator layer_iterator = layers.find(layer_id);
    if (layer_iterator == layers.end())
        return false;

    return layer_iterator->second->GenerateTexture(texture_data, texture_dimensions, texture_id);
}

// Generates the geometry required to render a single line of text.
int FontFaceHandle::GenerateString(GeometryList& geometry, const WString& string, const Vector2f& position, const Colourb& colour, int layer_configuration_index) const
{
    int geometry_index = 0;
    int line_width = 0;

    ROCKET_ASSERT(layer_configuration_index >= 0);
    ROCKET_ASSERT(layer_configuration_index < (int) layer_configurations.size());

    // Fetch the requested configuration and generate the geometry for each one.
    const LayerConfiguration& layer_configuration = layer_configurations[layer_configuration_index];
    for (size_t i = 0; i < layer_configuration.size(); ++i)
    {
        Rocket::Core::FontFaceLayer* layer = layer_configuration[i];

        Colourb layer_colour;
        if (layer == base_layer)
            layer_colour = colour;
        else
            layer_colour = layer->GetColour();

        // Resize the geometry list if required.
        if ((int) geometry.size() < geometry_index + layer->GetNumTextures())
            geometry.resize(geometry_index + layer->GetNumTextures());

        // Bind the textures to the geometries.
        for (int i = 0; i < layer->GetNumTextures(); ++i)
            geometry[geometry_index + i].SetTexture(layer->GetTexture(i));

        line_width = 0;
        word prior_character = 0;

        const word* string_iterator = string.CString();
        const word* string_end = string.CString() + string.Length();

        for (; string_iterator != string_end; string_iterator++)
        {
            if (*string_iterator >= glyphs.size())
                continue;
            const FontGlyph &glyph = glyphs[*string_iterator];

            // Adjust the cursor for the kerning between this character and the previous one.
            if (prior_character != 0)
                line_width += GetKerning(prior_character, *string_iterator);

            layer->GenerateGeometry(&geometry[geometry_index], *string_iterator, Vector2f(position.x + line_width, position.y), layer_colour);

            line_width += glyph.advance;
            prior_character = *string_iterator;
        }

        geometry_index += layer->GetNumTextures();
    }

    // Cull any excess geometry from a previous generation.
    geometry.resize(geometry_index);

    return line_width;
}

// Generates the geometry required to render a line above, below or through a line of text.
void FontFaceHandle::GenerateLine(Geometry* geometry, const Vector2f& position, int width, Font::Line height, const Colourb& colour) const
{
    std::vector< Vertex >& line_vertices = geometry->GetVertices();
    std::vector< int >& line_indices = geometry->GetIndices();

    float offset;
    switch (height)
    {
        case Font::UNDERLINE:			offset = -underline_position; break;
        case Font::OVERLINE:			// where to place? offset = -line_height - underline_position; break;
        case Font::STRIKE_THROUGH:		// where to place? offset = -line_height * 0.5f; break;
        default:						return;
    }

    line_vertices.resize(line_vertices.size() + 4);
    line_indices.resize(line_indices.size() + 6);
    GeometryUtilities::GenerateQuad(&line_vertices[0] + (line_vertices.size() - 4), &line_indices[0] + (line_indices.size() - 6), Vector2f(position.x, position.y + offset), Vector2f((float) width, underline_thickness), colour, line_vertices.size() - 4);
}

// Destroys the handle.
void FontFaceHandle::OnReferenceDeactivate()
{
    delete this;
}

void FontFaceHandle::GenerateMetrics(BitmapFontDefinitions *bm_face)
{
    line_height = bm_face->CommonCharactersInfo.LineHeight;
    baseline = bm_face->CommonCharactersInfo.BaseLine;

    underline_position = (float)line_height - bm_face->CommonCharactersInfo.BaseLine;//FT_MulFix(ft_face->underline_position, ft_face->size->metrics.y_scale) / float(1 << 6);
    /*underline_thickness = FT_MulFix(ft_face->underline_thickness, ft_face->size->metrics.y_scale) / float(1 << 6);
    underline_thickness = Math::Max(underline_thickness, 1.0f);
*/
    baseline += int( underline_position / 1.5f );
    underline_thickness = 1.0f;
    average_advance = 0;
    for (FontGlyphList::iterator i = glyphs.begin(); i != glyphs.end(); ++i)
        average_advance += i->advance;

    // Bring the total advance down to the average advance, but scaled up 10%, just to be on the safe side.
    average_advance = Math::RealToInteger((float) average_advance / (glyphs.size() * 0.9f));

    // Determine the x-height of this font face.
    word x = (word) 'x';
    int index = bm_face->BM_Helper_GetCharacterTableIndex( x );// FT_Get_Char_Index(ft_face, x);

    if ( index >= 0)
        x_height = bm_face->CharactersInfo[ index ].Height;
    else
        x_height = 0;
}

void FontFaceHandle::BuildGlyphMap(BitmapFontDefinitions *bm_face, const UnicodeRange& unicode_range)
{
    glyphs.resize(unicode_range.max_codepoint + 1);

    for (word character_code = (word) (Math::Max< unsigned int >(unicode_range.min_codepoint, 32)); character_code <= unicode_range.max_codepoint; ++character_code)
    {
        int index = bm_face->BM_Helper_GetCharacterTableIndex( character_code );

        if ( index < 0 )
        {
            continue;
        }

        FontGlyph glyph;
        glyph.character = character_code;
        BuildGlyph(glyph, &bm_face->CharactersInfo[ index ] );
        glyphs[character_code] = glyph;
    }
}

void Rocket::Core::BitmapFont::FontFaceHandle::BuildGlyph(FontGlyph& glyph, CharacterInfo *bm_glyph)
{
    // Set the glyph's dimensions.
    glyph.dimensions.x = bm_glyph->Width;
    glyph.dimensions.y = bm_glyph->Height;

    // Set the glyph's bearing.
    glyph.bearing.x = bm_glyph->XOffset;
    glyph.bearing.y = bm_glyph->YOffset;

    // Set the glyph's advance.
    glyph.advance = bm_glyph->Advance;

    // Set the glyph's bitmap position.
    glyph.bitmap_dimensions.x = bm_glyph->X;
    glyph.bitmap_dimensions.y = bm_glyph->Y;

    glyph.bitmap_data = NULL;
}

int Rocket::Core::BitmapFont::FontFaceHandle::GetKerning(word lhs, word rhs) const
{
    if( bm_face != NULL)
    {
        return bm_face->BM_Helper_GetXKerning(lhs, rhs);
    }

    return 0;
}

// Generates (or shares) a layer derived from a font effect.
Rocket::Core::FontFaceLayer* FontFaceHandle::GenerateLayer( FontEffect* font_effect)
{
    // See if this effect has been instanced before, as part of a different configuration.
    FontLayerMap::iterator i = layers.find(font_effect);
    if (i != layers.end())
        return i->second;

    Rocket::Core::FontFaceLayer* layer = new Rocket::Core::BitmapFont::FontFaceLayer();
    layers[font_effect] = layer;

    if (font_effect == NULL)
    {
        layer->Initialise(this);
    }
    else
    {
        // Determine which, if any, layer the new layer should copy its geometry and textures from.
        Rocket::Core::FontFaceLayer* clone = NULL;
        bool deep_clone = true;
        String generation_key;

        if (!font_effect->HasUniqueTexture())
        {
            clone = base_layer;
            deep_clone = false;
        }
        else
        {
            generation_key = font_effect->GetName() + ";" + font_effect->GetGenerationKey();
            FontLayerCache::iterator cache_iterator = layer_cache.find(generation_key);
            if (cache_iterator != layer_cache.end())
                clone = cache_iterator->second;
        }

        // Create a new layer.
        layer->Initialise(this, font_effect, clone, deep_clone);

        // Cache the layer in the layer cache if it generated its own textures (ie, didn't clone).
        if (clone == NULL)
            layer_cache[generation_key] = (Rocket::Core::FontFaceLayer*) layer;
    }

    return (Rocket::Core::FontFaceLayer*)layer;
}

}
}
}