Experiment: plugin GUI using XCB. (#3)

GUI doesn't actually do anything besides displaying a host-embedded
window with some basic graphics.

CHANGELOG.md

@@ -5,6 +5,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+### Added
+* Demonstration of plugin GUI using raw XCB calls.
+  The GUI is currently totally non-functional.
+
 ## [0.1.3] - 2024-01-24
 ### Changed
 * Plugin version is now source from V mod file.

Makefile

@@ -1,18 +1,17 @@
-SOURCEDIR = src
+SOURCEDIR = .
 BUILDDIR = build
 TARGET = $(BUILDDIR)/hello_world.clap
 V_CMD = v -cc gcc -shared -enable-globals
-
-# List all V source files
-V_SRC = $(wildcard $(SOURCEDIR)/*.v)
-
+V_SRC := $(shell find $(SOURCEDIR) -name '*.v' -o -name '*.c')
 
 # Debug and Release build options
 DEBUG ?= 0
 RELEASE ?= 0
 ifeq ($(DEBUG),1)
-	V_FLAGS = -cg -show-c-output
+	V_FLAGS = -cg
 else ifeq ($(DEBUG),2)
+	V_FLAGS = -cg -show-c-output
+else ifeq ($(DEBUG),3)
 	# Even more debug! Very noisy.
 	V_FLAGS = -cg -show-c-output -trace-calls
 else ifeq ($(RELEASE),1)

main.v

@@ -0,0 +1,14 @@
+import vclap
+// Exposes the plugin to the host (DAW).
+
+@[markused]
+__global clap_entry = vclap.plugin_entry
+// This requires modification to `clap/entry.h`.
+// Remove "const" so you get:
+// CLAP_EXPORT extern clap_plugin_entry_t clap_entry;
+
+fn init() {
+	$if debug {
+		eprintln('VCLAP in debug mode')
+	}
+}

vclap/.clang-format

@@ -0,0 +1,2 @@
+---
+IndentWidth:     4

src/c_abi.v → vclap/c_abi.v

@@ -1,4 +1,6 @@
-#flag -I./include
+module vclap
+
+#flag -I @VMODROOT/include
 #include "clap/clap.h"
 
 enum ClapProcessStatus {

src/ext_audio_ports.v → vclap/ext_audio_ports.v

@@ -1,3 +1,5 @@
+module vclap
+
 const clap_ext_audio_ports = unsafe { (&char(C.CLAP_EXT_AUDIO_PORTS)).vstring() }
 const clap_port_stereo = unsafe { (&char(C.CLAP_PORT_STEREO)).vstring() }
 const clap_port_mono = unsafe { (&char(C.CLAP_PORT_MONO)).vstring() }

vclap/ext_gui.v

@@ -0,0 +1,49 @@
+module vclap
+
+const clap_ext_gui = unsafe { (&char(C.CLAP_EXT_GUI)).vstring() }
+const clap_window_api_x11 = unsafe { (&char(C.CLAP_WINDOW_API_X11)).vstring() }
+const clap_window_api_wayland = unsafe { (&char(C.CLAP_WINDOW_API_WAYLAND)).vstring() }
+
+type C.clap_hwnd = voidptr
+type C.clap_nsview = voidptr
+type C.clap_xwnd = u32
+
+@[typedef]
+struct C.clap_window_t {
+	api &char
+	// union {
+	cocoa C.clap_nsview
+	x11   C.clap_xwnd
+	win32 C.clap_hwnd
+	ptr   voidptr
+	// }
+}
+
+@[typedef]
+struct C.clap_gui_resize_hints_t {
+	can_resize_horizontally bool
+	can_resize_vertically   bool
+	preserve_aspect_ratio   bool
+	aspect_ratio_width      u32
+	aspect_ratio_height     u32
+}
+
+@[typedef]
+struct C.clap_plugin_gui_t {
+	is_api_supported  fn (&C.clap_plugin_t, &char, bool) bool
+	// voidptr is &&char in original but used in a weird way.
+	get_preferred_api fn (&C.clap_plugin_t, voidptr, &bool) bool
+	create            fn (&C.clap_plugin_t, &char, bool) bool
+	destroy           fn (&C.clap_plugin_t)
+	set_scale         fn (&C.clap_plugin_t, f64) bool
+	get_size          fn (&C.clap_plugin_t, &u32, &u32) bool
+	can_resize        fn (&C.clap_plugin_t) bool
+	get_resize_hints  fn (&C.clap_plugin_t, &C.clap_gui_resize_hints_t) bool
+	adjust_size       fn (&C.clap_plugin_t, &u32, &u32) bool
+	set_size          fn (&C.clap_plugin_t, &u32, &u32) bool
+	set_parent        fn (&C.clap_plugin_t, &C.clap_window_t) bool
+	set_transient     fn (&C.clap_plugin_t, &C.clap_window_t) bool
+	suggest_title     fn (&C.clap_plugin_t, &char)
+	show              fn (&C.clap_plugin_t) bool
+	hide              fn (&C.clap_plugin_t) bool
+}

src/ext_latency.v → vclap/ext_latency.v

@@ -1,3 +1,5 @@
+module vclap
+
 const clap_ext_latency = unsafe { (&char(C.CLAP_EXT_LATENCY)).vstring() }
 
 @[typedef]

src/ext_note_ports.v → vclap/ext_note_ports.v

@@ -1,3 +1,5 @@
+module vclap
+
 const clap_ext_note_ports = unsafe { (&char(C.CLAP_EXT_NOTE_PORTS)).vstring() }
 
 @[typedef]

vclap/ext_posix_fd.v

@@ -0,0 +1,21 @@
+module vclap
+
+const clap_ext_posix_fd_support = unsafe { (&char(C.CLAP_EXT_POSIX_FD_SUPPORT)).vstring() }
+
+enum ClapPosixFDFlags as u32 {
+	read  = 1 << 0
+	write = 1 << 1
+	error = 1 << 2
+}
+
+@[typedef]
+struct C.clap_host_posix_fd_support_t {
+	register_fd   fn (&C.clap_host_t, int, ClapPosixFDFlags) bool
+	modify_fd     fn (&C.clap_host_t, int, ClapPosixFDFlags) bool
+	unregister_fd fn (&C.clap_host_t, int) bool
+}
+
+@[typedef]
+struct C.clap_plugin_posix_fd_support_t {
+	on_fd fn (&C.clap_plugin_t, int, ClapPosixFDFlags)
+}

vclap/gui/gui.v

@@ -0,0 +1,107 @@
+module gui
+
+@[heap]
+pub struct GUI {
+	width      u32
+	height     u32
+	connection &C.xcb_connection_t
+	window     C.xcb_window_t
+	gc         C.xcb_gcontext_t
+pub:
+	fd int
+}
+
+pub fn GUI.create(width u32, height u32, title string) &GUI {
+	// Open the connection to the X server.
+	conn := unsafe { C.xcb_connect(nil, nil) }
+	if isnil(conn) {
+		panic('Unable to open XCB connection.')
+	}
+
+	// Get the first screen.
+	screen := C.xcb_setup_roots_iterator(C.xcb_get_setup(conn)).data
+	// Create a window.
+	window := C.xcb_generate_id(conn)
+	C.xcb_create_window(conn, C.XCB_COPY_FROM_PARENT, window, screen.root, 0, 0, width,
+		height, 1, C.XCB_WINDOW_CLASS_INPUT_OUTPUT, screen.root_visual, C.XCB_CW_BACK_PIXEL,
+		&screen.white_pixel)
+
+	// Select the events the window will receive.
+	event_mask := C.XCB_EVENT_MASK_EXPOSURE | C.XCB_EVENT_MASK_POINTER_MOTION | C.XCB_EVENT_MASK_BUTTON_PRESS | C.XCB_EVENT_MASK_BUTTON_RELEASE | C.XCB_EVENT_MASK_KEY_PRESS | C.XCB_EVENT_MASK_KEY_RELEASE | C.XCB_EVENT_MASK_ENTER_WINDOW | C.XCB_EVENT_MASK_LEAVE_WINDOW | C.XCB_EVENT_MASK_BUTTON_MOTION | C.XCB_EVENT_MASK_KEYMAP_STATE | C.XCB_EVENT_MASK_FOCUS_CHANGE
+	C.xcb_change_window_attributes(conn, window, C.XCB_CW_EVENT_MASK, &event_mask)
+
+	// Inform a window manager not to tamper with the window
+	// Note: doesn't work in standalone.
+	C.xcb_change_window_attributes(conn, window, C.XCB_CW_OVERRIDE_REDIRECT, &[1]!)
+
+	// Create a graphic context to paint on.
+	gc := C.xcb_generate_id(conn)
+	gc_values := [screen.black_pixel, 0]!
+	C.xcb_create_gc(conn, gc, window, C.XCB_GC_FOREGROUND | C.XCB_GC_GRAPHICS_EXPOSURES,
+		&gc_values)
+
+	C.xcb_flush(conn)
+
+	return &GUI{
+		width: width
+		height: height
+		connection: conn
+		window: window
+		gc: gc
+		fd: C.xcb_get_file_descriptor(conn)
+	}
+}
+
+pub fn (g &GUI) destroy() {
+	C.xcb_free_gc(g.connection, g.gc)
+	C.xcb_destroy_window(g.connection, g.window)
+	C.xcb_disconnect(g.connection)
+}
+
+pub fn (g &GUI) set_parent(parent u32) {
+	C.xcb_reparent_window(g.connection, g.window, parent, 0, 0)
+	C.xcb_flush(g.connection)
+}
+
+pub fn (g &GUI) set_visible(visible bool) {
+	if visible {
+		C.xcb_configure_window(g.connection, g.window, C.XCB_CONFIG_WINDOW_STACK_MODE,
+			&[C.XCB_STACK_MODE_ABOVE]!)
+		C.xcb_map_window(g.connection, g.window)
+	} else {
+		C.xcb_unmap_window(g.connection, g.window)
+	}
+	C.xcb_flush(g.connection)
+}
+
+fn (g &GUI) paint() {
+	C.xcb_clear_area(g.connection, 0, g.window, 0, 0, g.width, g.height)
+	// Parameter "slider".
+	C.xcb_change_gc(g.connection, g.gc, C.XCB_GC_FOREGROUND, &[0]!)
+	C.xcb_poly_rectangle(g.connection, g.window, g.gc, 1, &C.xcb_rectangle_t{50, 50, 25, 100})
+	C.xcb_poly_fill_rectangle(g.connection, g.window, g.gc, 1, &C.xcb_rectangle_t{50, 50, 25, 40})
+}
+
+pub fn (g &GUI) on_posix_fd() {
+	C.xcb_flush(g.connection)
+
+	for {
+		event := C.xcb_poll_for_event(g.connection)
+		if isnil(event) {
+			break
+		}
+		t := event.response_type & ~0x80
+		match t {
+			u8(C.XCB_EXPOSE) {
+				expose_ev := &C.xcb_expose_event_t(event)
+				if expose_ev.window == g.window {
+					g.paint()
+				}
+			}
+			else {}
+		}
+
+		C.xcb_flush(g.connection)
+		C.free(event)
+	}
+}

vclap/gui/xcb.v

@@ -0,0 +1,79 @@
+module gui
+
+#pkgconfig --libs xcb
+
+#include <xcb/xcb.h>
+
+// XCB library
+type C.xcb_window_t = u32
+type C.xcb_gcontext_t = u32
+type C.xcb_visualid_t = u32
+type C.xcb_atom_t = u32
+
+@[typedef]
+struct C.xcb_connection_t {}
+
+@[typedef]
+struct C.xcb_setup_t {}
+
+@[typedef]
+struct C.xcb_screen_t {
+	root        C.xcb_window_t
+	root_visual C.xcb_visualid_t
+	white_pixel u32
+	black_pixel u32
+}
+
+@[typedef]
+struct C.xcb_screen_iterator_t {
+	data &C.xcb_screen_t
+}
+
+@[typedef]
+struct C.xcb_gcontext_t {}
+
+@[typedef]
+struct C.xcb_rectangle_t {
+	x      i16
+	y      i16
+	width  u16
+	height u16
+}
+
+@[typedef]
+struct C.xcb_generic_event_t {
+	response_type u8
+}
+
+@[typedef]
+struct C.xcb_expose_event_t {
+	window C.xcb_window_t
+}
+
+fn C.xcb_connect(&char, &int) &C.xcb_connection_t
+fn C.xcb_disconnect(&C.xcb_connection_t)
+fn C.xcb_flush(&C.xcb_connection_t)
+
+fn C.xcb_get_setup(&C.xcb_connection_t) &C.xcb_setup_t
+fn C.xcb_setup_roots_iterator(&C.xcb_setup_t) C.xcb_screen_iterator_t
+fn C.xcb_generate_id(&C.xcb_connection_t) u32
+fn C.xcb_get_file_descriptor(&C.xcb_connection_t) int
+
+fn C.xcb_create_window(&C.xcb_connection_t, u8, C.xcb_window_t, C.xcb_window_t, i16, i16, u16, u16, u16, u16, C.xcb_visualid_t, u32, voidptr)
+fn C.xcb_destroy_window(&C.xcb_connection_t, C.xcb_window_t)
+fn C.xcb_configure_window(&C.xcb_connection_t, C.xcb_window_t, u16, voidptr)
+fn C.xcb_change_window_attributes(&C.xcb_connection_t, C.xcb_window_t, u32, voidptr)
+fn C.xcb_reparent_window(&C.xcb_connection_t, C.xcb_window_t, C.xcb_window_t, i16, i16)
+fn C.xcb_map_window(&C.xcb_connection_t, C.xcb_window_t)
+fn C.xcb_unmap_window(&C.xcb_connection_t, C.xcb_window_t)
+
+fn C.xcb_create_gc(&C.xcb_connection_t, C.xcb_gcontext_t, C.xcb_window_t, u32, voidptr)
+fn C.xcb_free_gc(&C.xcb_connection_t, C.xcb_gcontext_t)
+fn C.xcb_change_gc(&C.xcb_connection_t, C.xcb_gcontext_t, u32, voidptr)
+
+fn C.xcb_clear_area(&C.xcb_connection_t, u8, C.xcb_window_t, i16, i16, u16, u16)
+fn C.xcb_poly_rectangle(&C.xcb_connection_t, C.xcb_window_t, C.xcb_gcontext_t, u32, &C.xcb_rectangle_t)
+fn C.xcb_poly_fill_rectangle(&C.xcb_connection_t, C.xcb_window_t, C.xcb_gcontext_t, u32, &C.xcb_rectangle_t)
+
+fn C.xcb_poll_for_event(&C.xcb_connection_t) &C.xcb_generic_event_t
+