WebCore/platform/wx/wxcode/gtk/fontprops.cpp

/*
 * Copyright (C) 2007 Kevin Ollivier <kevino@theolliviers.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <wx/defs.h>
#include <wx/gdicmn.h>
#include <wx/font.h>
#include <wx/fontutil.h>
#include "fontprops.h"

#include <gdk/gdk.h>

wxFontProperties::wxFontProperties(wxFont* font):
m_ascent(0), m_descent(0), m_lineGap(0), m_lineSpacing(0), m_xHeight(0)
{
    PangoContext* context = gdk_pango_context_get_for_screen( gdk_screen_get_default() );
    PangoLayout* layout = pango_layout_new(context);
    // and use it if it's valid
    if ( font && font->Ok() )
    {
        pango_layout_set_font_description
        (
            layout,
            font->GetNativeFontInfo()->description
        );
    }
    
    PangoFontMetrics* metrics = pango_context_get_metrics (context, font->GetNativeFontInfo()->description, NULL);

    int height = font->GetPixelSize().GetHeight();

    m_ascent = PANGO_PIXELS(pango_font_metrics_get_ascent(metrics)); 
    m_descent = PANGO_PIXELS(pango_font_metrics_get_descent(metrics));
    
    int h;

    const char* x = "x";
    pango_layout_set_text( layout, x, strlen(x) );
    pango_layout_get_pixel_size( layout, NULL, &h );
            
    m_xHeight = h;
    m_lineGap = (m_ascent + m_descent) / 4; // FIXME: How can we calculate this via Pango? 
    m_lineSpacing = m_ascent + m_descent;

    pango_font_metrics_unref(metrics);
}

void GetTextExtent( const wxFont& font, const wxString& str, wxCoord *width, wxCoord *height,
                            wxCoord *descent, wxCoord *externalLeading )
{
    if ( width )
        *width = 0;
    if ( height )
        *height = 0;
    if ( descent )
        *descent = 0;
    if ( externalLeading )
        *externalLeading = 0;

    if (str.empty())
        return;
        
    PangoContext* context = gdk_pango_context_get_for_screen( gdk_screen_get_default() );
    PangoLayout* m_layout = pango_layout_new(context);
    // and use it if it's valid
    if ( font != wxNullFont )
    {
        pango_layout_set_font_description
        (
            m_layout,
            font.GetNativeFontInfo()->description
        );
    }

    // Set layout's text
    const wxCharBuffer dataUTF8 = wxConvUTF8.cWX2MB(str);
    if ( !dataUTF8 )
    {
        // hardly ideal, but what else can we do if conversion failed?
        return;
    }

    pango_layout_set_text( m_layout, dataUTF8, strlen(dataUTF8) );

    if (descent)
    {
        int h;
        pango_layout_get_pixel_size( m_layout, width, &h );
        PangoLayoutIter *iter = pango_layout_get_iter(m_layout);
        int baseline = pango_layout_iter_get_baseline(iter);
        pango_layout_iter_free(iter);
        *descent = h - PANGO_PIXELS(baseline);

        if (height)
            *height = (wxCoord) h;
    }
    else
    {
        pango_layout_get_pixel_size( m_layout, width, height );
    }

    // Reset old font description
    //if (font != wxNullFont)
    //    pango_layout_set_font_description( m_layout, m_fontdesc );
}