自学教程：C++ update_canvas函数代码示例

void ttext_box::update_offsets(){	assert(config());	boost::intrusive_ptr<const ttext_box_definition::tresolution>	conf = boost::dynamic_pointer_cast<const ttext_box_definition::tresolution>(			config());	assert(conf);	text_height_ = font::get_max_height(conf->text_font_size);	game_logic::map_formula_callable variables;	variables.add("height", variant(get_height()));	variables.add("width", variant(get_width()));	variables.add("text_font_height", variant(text_height_));	text_x_offset_ = conf->text_x_offset(variables);	text_y_offset_ = conf->text_y_offset(variables);	// Since this variable doesn't change set it here instead of in	// update_canvas().	for(auto & tmp : canvas())	{		tmp.set_variable("text_font_height", variant(text_height_));	}	// Force an update of the canvas since now text_font_height is known.	update_canvas();}

int GraphicGUI::resize_event(int w, int h){	int difference = h - get_h();	int canvas_xdiff = get_w() - canvas->get_w();	int canvas_ydiff = get_h() - canvas->get_h();		canvas->reposition_window(canvas->get_x(),		canvas->get_y(),		w - canvas_xdiff,		h - canvas_ydiff);	freq_text->reposition_window(freq_text->get_x(),		freq_text->get_y() + difference);	value_text->reposition_window(value_text->get_x(),		value_text->get_y() + difference);	freq_title->reposition_window(freq_title->get_x(),		freq_title->get_y() + difference);	level_title->reposition_window(level_title->get_x(),		level_title->get_y() + difference);	size_title->reposition_window(size_title->get_x(),		size_title->get_y() + difference);	reset->reposition_window(reset->get_x(),		reset->get_y() + difference);	size->reposition_window(size->get_x(),		size->get_y() + difference);	draw_ticks();	update_canvas();	flash();	plugin->w = w;	plugin->h = h;	plugin->send_configure_change();	return 1;}

void ttext_::set_selection(size_t start, int length){	const size_t text_size = text_.get_length();	if(start >= text_size) {		start = text_size;	}	if(length == 0) {		set_cursor(start, false);		return;	}	// The text pos/size type differs in both signedness and size with the	// selection length. Such is life.	const int sel_start = std::min<size_t>(start, std::numeric_limits<int>::max());	const int sel_max_length = std::min<size_t>(text_size - start, std::numeric_limits<int>::max());	const bool backwards = length < 0;	if(backwards && -length > sel_start) {		length = -sel_start;	} else if(!backwards && length > sel_max_length) {		length = sel_max_length;	}	set_selection_start(start);	set_selection_length(length);	update_canvas();}

void ParametricWindow::update_gui(){	for(int i = 0; i < BANDS; i++)		bands[i]->update_gui();	wetness->update(plugin->config.wetness);	size->update(plugin->config.window_size);	update_canvas();}

void tlabel::set_link_color(const std::string & color){	if(color == link_color_) {		return;	}	link_color_ = color;	update_canvas();	set_is_dirty(true);}

void GraphicGUI::create_objects(){	int margin = plugin->get_theme()->widget_border;	int x = get_text_width(SMALLFONT, "-00") + LINE_W4 + margin;	int y = margin;	int freq_h = get_text_height(SMALLFONT) + LINE_W4;	add_subwindow(canvas = new GraphicCanvas(plugin,		this,		x, 		y, 		get_w() - x - margin, 		get_h() - //			BC_Pot::calculate_h() - 			BC_TextBox::calculate_h(this, MEDIUMFONT, 1, 1) -			margin * 3 - 			y - 			freq_h));	y += canvas->get_h() + freq_h + margin;	int x1 = x;	int y1 = y;	add_subwindow(freq_title = new BC_Title(x, y, "Frequency:"));	x += freq_title->get_w() + margin;	add_subwindow(freq_text = new FreqTextBox(plugin, this, x, y, 100));	x += freq_text->get_w() + margin;	add_subwindow(level_title = new BC_Title(x, y, "Level:"));	x += level_title->get_w() + margin;	add_subwindow(value_text = new ValueTextBox(plugin, this, x, y, 100));	x += value_text->get_w() + margin;	add_subwindow(reset = new GraphicReset(plugin, this, x, y));	x += reset->get_w() + margin;	//	x = x1;//	y += value_text->get_h() + margin;	add_subwindow(size_title = new BC_Title(x, y, "Window size:"));	x += size_title->get_w() + margin;	add_subwindow(size = new GraphicSize(this, plugin, x, y));	size->create_objects();	size->update(plugin->config.window_size);	x += size->get_w() + margin;//	add_subwindow(title = new BC_Title(x, y, "Wetness:"));//	x += title->get_w() + margin;// 	add_subwindow(wetness = new GraphicWetness(this, plugin, // 		x, // 		y));	draw_ticks();	update_canvas();	show_window();}

void tcontrol::set_text_alignment(const PangoAlignment text_alignment){	if(text_alignment_ == text_alignment) {		return;	}	text_alignment_ = text_alignment;	update_canvas();	set_is_dirty(true);}

void tcontrol::set_label(const t_string& label){	if(label == label_) {		return;	}	label_ = label;	set_layout_size(tpoint(0, 0));	update_canvas();	set_is_dirty(true);}

void ttext_::insert_char(const utf8::string& unicode){	delete_selection();	if(text_.insert_text(selection_start_, unicode)) {		// Update status		set_cursor(selection_start_ + 1, false);		update_canvas();		set_is_dirty(true);	}}

void ttext_::paste_selection(const bool mouse){	const std::string& text = copy_from_clipboard(mouse);	if(text.empty()) {		return;	}	delete_selection();	selection_start_ += text_.insert_text(selection_start_, text);	update_canvas();	set_dirty();}

void tpanel::set_hole_variable(int left, int right){	if (left < 0 || right < 0) {		return;	}	if (left != hole_left_ || right != hole_right_) {		hole_left_ = left;		hole_right_ = right;		if (x_ >= 0) {			update_canvas();			set_dirty();		}	}}

static void frame_timer_callback(void *data){	struct timeval prev;	getuptime(&prev);		frame++;	if (frame >= FRAMES)		frame = 0;		update_canvas(frame_canvas, frames[frame]);		struct timeval cur;	getuptime(&cur);		plan_frame_timer(tv_sub_diff(&cur, &prev));}

void CompressorWindow::create_objects(){	int x = 35, y = 10;	int control_margin = 130;	add_subwindow(canvas = new CompressorCanvas(plugin, 		x, 		y, 		get_w() - x - control_margin - 10, 		get_h() - y - 70));	canvas->set_cursor(CROSS_CURSOR, 0, 0);	x = get_w() - control_margin;	add_subwindow(new BC_Title(x, y, _("Reaction secs:")));	y += 20;	add_subwindow(reaction = new CompressorReaction(plugin, x, y));	y += 30;	add_subwindow(new BC_Title(x, y, _("Decay secs:")));	y += 20;	add_subwindow(decay = new CompressorDecay(plugin, x, y));	y += 30;	add_subwindow(new BC_Title(x, y, _("Trigger Type:")));	y += 20;	add_subwindow(input = new CompressorInput(plugin, x, y));	input->create_objects();	y += 30;	add_subwindow(new BC_Title(x, y, _("Trigger:")));	y += 20;	add_subwindow(trigger = new CompressorTrigger(plugin, x, y));	if(plugin->config.input != CompressorConfig::TRIGGER) trigger->disable();	y += 30;	add_subwindow(smooth = new CompressorSmooth(plugin, x, y));	y += 60;	add_subwindow(clear = new CompressorClear(plugin, x, y));	x = 10;	y = get_h() - 40;	add_subwindow(new BC_Title(x, y, _("Point:")));	x += 50;	add_subwindow(x_text = new CompressorX(plugin, x, y));	x += 110;	add_subwindow(new BC_Title(x, y, _("x")));	x += 20;	add_subwindow(y_text = new CompressorY(plugin, x, y));	draw_scales();	update_canvas();	show_window();}

void tscrollbar_::set_item_position(const unsigned item_position){	// Set the value always execute since we update a part of the state.	item_position_ = item_position > item_count_ - visible_items_			? item_count_ - visible_items_			: item_position;	item_position_ = (item_position_ + step_size_ - 1) / step_size_;	if(all_items_visible()) {		item_position_ = 0;	}	// Determine the pixel offset of the item position.	positioner_offset_ = static_cast<unsigned>(item_position_ * pixels_per_step_);	update_canvas();	assert(item_position_ <= item_count_ - visible_items_);}

void ttext_box::handle_mouse_selection(tpoint mouse, const bool start_selection){	mouse.x -= get_x();	mouse.y -= get_y();	// FIXME we don't test for overflow in width	if(mouse.x < static_cast<int>(text_x_offset_)	   || mouse.y < static_cast<int>(text_y_offset_)	   || mouse.y >= static_cast<int>(text_y_offset_ + text_height_)) {		return;	}	int offset = get_column_line(tpoint(mouse.x - text_x_offset_, mouse.y - text_y_offset_)).x;	if(offset < 0) {		return;	}	set_cursor(offset, !start_selection);	update_canvas();	set_is_dirty(true);	dragging_ |= start_selection;}

	void set_icon_name(const std::string& icon_name)		{ icon_name_ = icon_name; update_canvas(); }