void gtk_glwidget_create_font(){
PangoFontDescription *font_desc;
PangoLayout *layout;
PangoRectangle log_rect;
int font_ascent_pango_units;
int font_descent_pango_units;
if ( _debug_font_created ) {
Error( "Programming error: gtk_glwidget_create_font() was already called; "
"you must call gtk_glwidget_destroy_font() before creating font again" );
}
_debug_font_created = 1;
font_map = pango_ft2_font_map_new();
pango_ft2_font_map_set_resolution( PANGO_FT2_FONT_MAP( font_map ), 72, 72 );
ft2_context = pango_font_map_create_context( PANGO_FONT_MAP( font_map ));
font_desc = pango_font_description_from_string( font_string );
pango_font_description_set_size( font_desc, font_height * PANGO_SCALE );
pango_context_set_font_description( ft2_context, font_desc );
pango_font_description_free( font_desc );
layout = pango_layout_new( ft2_context );
// I don't believe that's standard preprocessor syntax?
#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 );
y_offset_bitmap_render_pango_units = ( font_ascent * PANGO_SCALE ) - font_ascent_pango_units;
}
static void
gnm_notebook_button_get_preferred_width (GtkWidget *widget,
gint *minimum,
gint *natural)
{
GnmNotebookButton *nbb = GNM_NOTEBOOK_BUTTON (widget);
GtkBorder padding;
gtk_style_context_get_padding (gtk_widget_get_style_context (widget),
GTK_STATE_FLAG_NORMAL,
&padding);
gnm_notebook_button_ensure_layout (nbb);
*minimum = *natural =
(padding.left +
PANGO_PIXELS_CEIL (MAX (nbb->logical.width,
nbb->logical_active.width)) +
padding.right);
}
// 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".
void gtk_glwidget_print_string( 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;
if ( !_debug_font_created ) {
Error( "Programming error: gtk_glwidget_print_string() called but font does not exist; "
"you should have called gtk_glwidget_create_font() first" );
}
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 );
qglGetFloatv( 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.
qglGetIntegerv( GL_UNPACK_ALIGNMENT, &previous_unpack_alignment );
previous_blend_enabled = qglIsEnabled( GL_BLEND );
qglGetIntegerv( GL_BLEND_SRC, &previous_blend_func_src );
qglGetIntegerv( GL_BLEND_DST, &previous_blend_func_dst );
qglGetFloatv( GL_RED_BIAS, &previous_red_bias );
qglGetFloatv( GL_GREEN_BIAS, &previous_green_bias );
qglGetFloatv( GL_BLUE_BIAS, &previous_blue_bias );
qglGetFloatv( GL_ALPHA_SCALE, &previous_alpha_scale );
qglPixelStorei( GL_UNPACK_ALIGNMENT, 1 );
qglEnable( GL_BLEND );
qglBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
qglPixelTransferf( GL_RED_BIAS, color[0] );
qglPixelTransferf( GL_GREEN_BIAS, color[1] );
qglPixelTransferf( GL_BLUE_BIAS, color[2] );
qglPixelTransferf( GL_ALPHA_SCALE, color[3] );
qglDrawPixels( 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.
qglPixelTransferf( GL_ALPHA_SCALE, previous_alpha_scale );
qglPixelTransferf( GL_BLUE_BIAS, previous_blue_bias );
qglPixelTransferf( GL_GREEN_BIAS, previous_green_bias );
qglPixelTransferf( GL_RED_BIAS, previous_red_bias );
qglBlendFunc( previous_blend_func_src, previous_blend_func_dst );
if ( !previous_blend_enabled ) {
qglDisable( GL_BLEND );
}
qglPixelStorei( GL_UNPACK_ALIGNMENT, previous_unpack_alignment );
}
g_object_unref( G_OBJECT( layout ) );
}
