vmap/libs/gtkutil/glfont.cpp

/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "glfont.h"
#include "globaldefs.h"
#include "igl.h"

// generic string printing with call lists
class GLFontCallList : public GLFont {
    GLuint m_displayList;
    int m_pixelHeight;
    int m_pixelAscent;
    int m_pixelDescent;
public:
    GLFontCallList(GLuint displayList, int asc, int desc, int pixelHeight) : m_displayList(displayList),
                                                                             m_pixelHeight(pixelHeight),
                                                                             m_pixelAscent(asc), m_pixelDescent(desc)
    {
    }

    virtual ~GLFontCallList()
    {
        glDeleteLists(m_displayList, 256);
    }

    void printString(const char *s)
    {
        GlobalOpenGL().m_glListBase(m_displayList);
        GlobalOpenGL().m_glCallLists(GLsizei(strlen(s)), GL_UNSIGNED_BYTE, reinterpret_cast<const GLubyte *>( s ));
    }

    virtual int getPixelAscent() const
    {
        return m_pixelAscent;
    }

    virtual int getPixelDescent() const
    {
        return m_pixelDescent;
    }

    virtual int getPixelHeight() const
    {
        return m_pixelHeight;
    }
};

#if GDEF_OS_WINDOWS
#include <windows.h>
#endif

#include "debugging/debugging.h"

// LordHavoc: this is code for direct Xlib bitmap character fetching, as an
// alternative to requiring gtkglarea, it was created due to a lack of this
// package on SuSE 9.x but this package is now commonly shipping in Linux
// distributions so this code may be unnecessary, feel free however to enable
// it when building packages for distros that do not ship with that package,
// or if you just prefer less dependencies...
#if 0

#include <X11/Xlib.h>
#include <gdk/gdkx.h>
#include <GL/glx.h>

GLFont *glfont_create( const char* font_string ){
    GLuint font_list_base;
    XFontStruct *fontInfo;
    Display *dpy = GDK_DISPLAY();
    unsigned int i, first, last, firstrow, lastrow;
    int maxchars;
    int firstbitmap;

    fontInfo = XLoadQueryFont( dpy, "-*-fixed-*-*-*-*-8-*-*-*-*-*-*-*" );
    if ( fontInfo == NULL ) {
        // try to load other fonts
        fontInfo = XLoadQueryFont( dpy, "-*-fixed-*-*-*-*-*-*-*-*-*-*-*-*" );

        // any font will do !
        if ( fontInfo == NULL ) {
            fontInfo = XLoadQueryFont( dpy, "-*-*-*-*-*-*-*-*-*-*-*-*-*-*" );
        }

        if ( fontInfo == NULL ) {
            ERROR_MESSAGE( "couldn't create font" );
        }
    }

    first = (int)fontInfo->min_char_or_byte2;
    last = (int)fontInfo->max_char_or_byte2;
    firstrow = (int)fontInfo->min_byte1;
    lastrow = (int)fontInfo->max_byte1;
    /*
     * How many chars in the charset
     */
    maxchars = 256 * lastrow + last;
    font_list_base = glGenLists( maxchars + 1 );
    if ( font_list_base == 0 ) {
        ERROR_MESSAGE( "couldn't create font" );
    }

    /*
     * Get offset to first char in the charset
     */
    firstbitmap = 256 * firstrow + first;
    /*
     * for each row of chars, call glXUseXFont to build the bitmaps.
     */

    for ( i = firstrow; i <= lastrow; i++ )
    {
        glXUseXFont( fontInfo->fid, firstbitmap, last - first + 1, font_list_base + firstbitmap );
        firstbitmap += 256;
    }

/*    *height = fontInfo->ascent + fontInfo->descent;
 *width = fontInfo->max_bounds.width;  */
    return new GLFontCallList( font_list_base, fontInfo->ascent, fontInfo->descent, fontInfo->ascent + fontInfo->descent );
}

#elif 0

#include <gtk/gtkglwidget.h>

GLFont *glfont_create( const char* font_string ){
    GLuint font_list_base = glGenLists( 256 );
    gint font_height = 0, font_ascent = 0, font_descent = 0;

    PangoFontDescription* font_desc = pango_font_description_from_string( font_string );

    PangoFont* font = gdk_gl_font_use_pango_font( font_desc, 0, 256, font_list_base );

    if ( font == 0 ) {
        pango_font_description_free( font_desc );
        font_desc = pango_font_description_from_string( "fixed 8" );
        font = gdk_gl_font_use_pango_font( font_desc, 0, 256, font_list_base );
    }

    if ( font == 0 ) {
        pango_font_description_free( font_desc );
        font_desc = pango_font_description_from_string( "courier new 8" );
        font = gdk_gl_font_use_pango_font( font_desc, 0, 256, font_list_base );
    }

    if ( font != 0 ) {
        PangoFontMetrics* font_metrics = pango_font_get_metrics( font, 0 );

        font_ascent = pango_font_metrics_get_ascent( font_metrics );
        font_descent = pango_font_metrics_get_descent( font_metrics );
        font_height = font_ascent + font_descent;

        font_ascent = PANGO_PIXELS( font_ascent );
        font_descent = PANGO_PIXELS( font_descent );
        font_height = PANGO_PIXELS( font_height );

        pango_font_metrics_unref( font_metrics );
    }

    pango_font_description_free( font_desc );

    // fix for pango/gtkglext metrix bug
    if ( font_height > 256 ) {
        font_height = 16;
    }

    return new GLFontCallList( font_list_base, font_ascent, font_descent, font_height );
}
#else

// new font code ripped from ZeroRadiant

#include <pango/pangoft2.h>
#include <pango/pango-features.h>
#include <pango/pango-utils.h>

class GLFontInternal : public GLFont {
    const char *font_string;
    int font_height;
    int font_ascent;
    int font_descent;
    int y_offset_bitmap_render_pango_units;
    PangoContext *ft2_context;
    PangoFontMap *fontmap;

public:
    GLFontInternal(const char *_font_string) : font_string(_font_string)
    {
        PangoFontDescription *font_desc;
        PangoLayout *layout;
        PangoRectangle log_rect;
        int font_ascent_pango_units;
        int font_descent_pango_units;

#if !PANGO_VERSION_CHECK(1, 22, 0)
        ft2_context = pango_ft2_get_context( 72, 72 );
#else
        fontmap = pango_ft2_font_map_new();
        pango_ft2_font_map_set_resolution(PANGO_FT2_FONT_MAP(fontmap), 72, 72);
        ft2_context = pango_font_map_create_context(fontmap);
#endif

        font_desc = pango_font_description_from_string( "Liberation Mono 12" );
        //pango_font_description_set_size(font_desc, 10 * PANGO_SCALE);
        pango_context_set_font_description(ft2_context, font_desc);
        pango_font_description_free(font_desc);
        // TODO fallback to fixed 8, courier new 8

        layout = pango_layout_new(ft2_context);

#ifdef FONT_SIZE_WORKAROUND
        pango_layout_set_width( layout, -1 );   // -1 no wrapping.  All text on one line.
        pango_layout_set_text( layout, "The quick brown fox jumped over the lazy sleeping dog's back then sat on a tack.", -1 );   // -1 null-terminated string.
#endif

#if !PANGO_VERSION_CHECK(1, 22, 0)
        PangoLayoutIter *iter;
        iter = pango_layout_get_iter( layout );
        font_ascent_pango_units = pango_layout_iter_get_baseline( iter );
        pango_layout_iter_free( iter );
#else
        font_ascent_pango_units = pango_layout_get_baseline(layout);
#endif
        pango_layout_get_extents(layout, NULL, &log_rect);
        g_object_unref(G_OBJECT(layout));
        font_descent_pango_units = log_rect.height - font_ascent_pango_units;

        font_ascent = PANGO_PIXELS_CEIL(font_ascent_pango_units);
        font_descent = PANGO_PIXELS_CEIL(font_descent_pango_units);
        font_height = font_ascent + font_descent;
        y_offset_bitmap_render_pango_units = (font_ascent * PANGO_SCALE) - font_ascent_pango_units;
    }

    virtual ~GLFontInternal()
    {
        g_object_unref(G_OBJECT(ft2_context));
        g_object_unref(G_OBJECT(fontmap));
    }

// Renders the input text at the current location with the current color.
// The X position of the current location is used to place the left edge of the text image,
// where the text image bounds are defined as the logical extents of the line of text.
// The Y position of the current location is used to place the bottom of the text image.
// You should offset the Y position by the amount returned by gtk_glwidget_font_descent()
// if you want to place the baseline of the text image at the current Y position.
// Note: A problem with this function is that if the lower left corner of the text falls
// just a hair outside of the viewport (meaning the current raster position is invalid),
// then no text will be rendered.  The solution to this is a very hacky one.  You can search
// Google for "glDrawPixels clipping".
    virtual void printString(const char *s)
    {
        // The idea for this code initially came from the font-pangoft2.c example that comes with GtkGLExt.

        PangoLayout *layout;
        PangoRectangle log_rect;
        FT_Bitmap bitmap;
        unsigned char *begin_bitmap_buffer;
        GLfloat color[4];
        GLint previous_unpack_alignment;
        GLboolean previous_blend_enabled;
        GLint previous_blend_func_src;
        GLint previous_blend_func_dst;
        GLfloat previous_red_bias;
        GLfloat previous_green_bias;
        GLfloat previous_blue_bias;
        GLfloat previous_alpha_scale;

        layout = pango_layout_new(ft2_context);
        pango_layout_set_width(layout, -1);   // -1 no wrapping.  All text on one line.
        pango_layout_set_text(layout, s, -1);   // -1 null-terminated string.
        pango_layout_get_extents(layout, NULL, &log_rect);

        if (log_rect.width > 0 && log_rect.height > 0) {
            bitmap.rows = font_ascent + font_descent;
            bitmap.width = PANGO_PIXELS_CEIL(log_rect.width);
            bitmap.pitch = -bitmap.width;     // Rendering it "upside down" for OpenGL.
            begin_bitmap_buffer = (unsigned char *) g_malloc(bitmap.rows * bitmap.width);
            memset(begin_bitmap_buffer, 0, bitmap.rows * bitmap.width);
            bitmap.buffer = begin_bitmap_buffer + (bitmap.rows - 1) * bitmap.width;   // See pitch above.
            bitmap.num_grays = 0xff;
            bitmap.pixel_mode = FT_PIXEL_MODE_GRAY;
            pango_ft2_render_layout_subpixel(&bitmap, layout, -log_rect.x,
                                             y_offset_bitmap_render_pango_units);
            GlobalOpenGL().m_glGetFloatv(GL_CURRENT_COLOR, color);

            // Save state.  I didn't see any OpenGL push/pop operations for these.
            // Question: Is saving/restoring this state necessary?  Being safe.
            GlobalOpenGL().m_glGetIntegerv(GL_UNPACK_ALIGNMENT, &previous_unpack_alignment);
            previous_blend_enabled = GlobalOpenGL().m_glIsEnabled(GL_BLEND);
            GlobalOpenGL().m_glGetIntegerv(GL_BLEND_SRC, &previous_blend_func_src);
            GlobalOpenGL().m_glGetIntegerv(GL_BLEND_DST, &previous_blend_func_dst);
            GlobalOpenGL().m_glGetFloatv(GL_RED_BIAS, &previous_red_bias);
            GlobalOpenGL().m_glGetFloatv(GL_GREEN_BIAS, &previous_green_bias);
            GlobalOpenGL().m_glGetFloatv(GL_BLUE_BIAS, &previous_blue_bias);
            GlobalOpenGL().m_glGetFloatv(GL_ALPHA_SCALE, &previous_alpha_scale);

            GlobalOpenGL().m_glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
            GlobalOpenGL().m_glEnable(GL_BLEND);
            GlobalOpenGL().m_glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            GlobalOpenGL().m_glPixelTransferf(GL_RED_BIAS, color[0]);
            GlobalOpenGL().m_glPixelTransferf(GL_GREEN_BIAS, color[1]);
            GlobalOpenGL().m_glPixelTransferf(GL_BLUE_BIAS, color[2]);
            GlobalOpenGL().m_glPixelTransferf(GL_ALPHA_SCALE, color[3]);

            GlobalOpenGL().m_glDrawPixels(bitmap.width, bitmap.rows,
                                          GL_ALPHA, GL_UNSIGNED_BYTE, begin_bitmap_buffer);
            g_free(begin_bitmap_buffer);

            // Restore state in reverse order of how we set it.
            GlobalOpenGL().m_glPixelTransferf(GL_ALPHA_SCALE, previous_alpha_scale);
            GlobalOpenGL().m_glPixelTransferf(GL_BLUE_BIAS, previous_blue_bias);
            GlobalOpenGL().m_glPixelTransferf(GL_GREEN_BIAS, previous_green_bias);
            GlobalOpenGL().m_glPixelTransferf(GL_RED_BIAS, previous_red_bias);
            GlobalOpenGL().m_glBlendFunc(previous_blend_func_src, previous_blend_func_dst);
            if (!previous_blend_enabled) {
                GlobalOpenGL().m_glDisable(GL_BLEND);
            }
            GlobalOpenGL().m_glPixelStorei(GL_UNPACK_ALIGNMENT, previous_unpack_alignment);
        }

        g_object_unref(G_OBJECT(layout));
    }

    virtual int getPixelAscent() const
    {
        return font_ascent;
    }

    virtual int getPixelDescent() const
    {
        return font_descent;
    }

    virtual int getPixelHeight() const
    {
        return font_height;
    }
};

GLFont *glfont_create(const char *font_string)
{
    return new GLFontInternal(font_string);
}

#endif