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 ) ); }