util/gpu/web/hb-gpu-web.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright (C) 2026  Behdad Esfahbod
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Author(s): Behdad Esfahbod
  */

 /*
  * Web (Emscripten) build of the hb-gpu demo.
  *
  * Reuses the desktop demo code with two changes:
  *   1. emscripten_set_main_loop replaces the blocking while loop
  *   2. HB_GPU_ATLAS_2D is defined (WebGL2 lacks texture buffers)
  *
  * Build:
  *   source emsdk/emsdk_env.sh
  *   ./util/gpu/web/build.sh
  *
  * Serve:
  *   python3 -m http.server -d util/gpu/web/out
  */

 #include <emscripten.h>
 #include <emscripten/html5.h>

 /* Pull in the demo code — all headers are self-contained */
 #include "../demo-common.h"
 #include "../demo-buffer.h"
 #include "../demo-font.h"
 #include "../demo-renderer.h"
 #include "../demo-view.h"

 #include "../default-text-combined.hh"
 #include "../default-text-en.hh"
 #include "../default-font.hh"

 static demo_renderer_t *renderer;
 static demo_view_t *vu;
 static demo_buffer_t *buffer;
 static demo_font_t *current_demo_font;
 static hb_blob_t *current_blob;
 static hb_face_t *current_face;
 static hb_font_t *current_font;
 static char *current_text;
 static bool custom_text;

 static void
 rebuild_buffer (const char *text)
 {
   free (current_text);
   current_text = strdup (text);

   demo_font_clear_cache (current_demo_font);
   demo_atlas_clear (renderer->get_atlas ());

   demo_buffer_clear (buffer);
   demo_point_t top_left = {0, 0};
   demo_buffer_move_to (buffer, &top_left);
   demo_buffer_add_text (buffer, text, current_demo_font, 1);
   demo_view_reset (vu);
   demo_view_display (vu, buffer);
 }

 extern "C" {

 EMSCRIPTEN_KEEPALIVE void
 web_load_font (const char *data, int len)
 {
   hb_blob_t *blob = hb_blob_create (data, len,
 				     HB_MEMORY_MODE_DUPLICATE,
 				     NULL, NULL);
   hb_face_t *face = hb_face_create (blob, 0);
   hb_font_t *font = hb_font_create (face);

   hb_blob_destroy (current_blob);
   hb_face_destroy (current_face);
   hb_font_destroy (current_font);

   current_blob = blob;
   current_face = face;
   current_font = font;

   /* Flush old font state */
   demo_font_destroy (current_demo_font);
   current_demo_font = demo_font_create (font, renderer->get_atlas ());

   rebuild_buffer (custom_text ? current_text : default_text_en);
   demo_font_print_stats (current_demo_font);
 }

 EMSCRIPTEN_KEEPALIVE void
 web_set_text (const char *utf8)
 {
   custom_text = true;
   rebuild_buffer (utf8);
 }

 EMSCRIPTEN_KEEPALIVE const char *
 web_get_text ()
 {
   return current_text;
 }

 EMSCRIPTEN_KEEPALIVE void
 web_toggle_animation ()
 {
   demo_view_key_func (vu, 32 /* GLFW_KEY_SPACE */, 0, 1, 0);
 }

 EMSCRIPTEN_KEEPALIVE void
 web_reset ()
 {
   demo_view_reset (vu);
 }

 EMSCRIPTEN_KEEPALIVE void
 web_request_redraw ()
 {
   demo_view_request_redraw (vu);
 }

 EMSCRIPTEN_KEEPALIVE void
 web_cancel_gesture ()
 {
   demo_view_cancel_gesture (vu);
 }

 EMSCRIPTEN_KEEPALIVE void
 web_pinch (float pan_dx, float pan_dy,
 	   float zoom_factor, float angle_delta,
 	   float cx, float cy, int w, int h)
 {
   demo_view_pinch (vu, pan_dx, pan_dy, zoom_factor, angle_delta, cx, cy, w, h);
 }

 } /* extern "C" */

 static void
 main_loop_iter ()
 {
   glfwPollEvents ();

   if (demo_view_should_redraw (vu))
     demo_view_display (vu, buffer);
 }

 static void
 framebuffer_size_func (GLFWwindow *window, int width, int height)
 { demo_view_reshape_func (vu, width, height); }

 static void
 key_func (GLFWwindow *window, int key, int scancode, int action, int mods)
 { demo_view_key_func (vu, key, scancode, action, mods); }

 static void
 char_func (GLFWwindow *window, unsigned int codepoint)
 { demo_view_char_func (vu, codepoint); }

 static void
 mouse_func (GLFWwindow *window, int button, int action, int mods)
 { demo_view_mouse_func (vu, button, action, mods); }

 static void
 scroll_func (GLFWwindow *window, double xoffset, double yoffset)
 { demo_view_scroll_func (vu, xoffset, yoffset); }

 static void
 cursor_func (GLFWwindow *window, double x, double y)
 { demo_view_motion_func (vu, x, y); }

 int
 main ()
 {
   if (!glfwInit ())
   {
     fprintf (stderr, "Failed to initialize GLFW\n");
     return 1;
   }

   glfwWindowHint (GLFW_CONTEXT_VERSION_MAJOR, 3);
   glfwWindowHint (GLFW_CONTEXT_VERSION_MINOR, 0);
   glfwWindowHint (GLFW_CLIENT_API, GLFW_OPENGL_ES_API);

   /* Query actual canvas size from the browser. */
   int canvas_w = 700, canvas_h = 700;
   emscripten_get_canvas_element_size ("#canvas", &canvas_w, &canvas_h);

   GLFWwindow *window = glfwCreateWindow (canvas_w, canvas_h, "HarfBuzz GPU Demo", NULL, NULL);
   if (!window)
   {
     glfwTerminate ();
     fprintf (stderr, "Failed to create GLFW window\n");
     return 1;
   }
   glfwMakeContextCurrent (window);

   glfwSetFramebufferSizeCallback (window, framebuffer_size_func);
   glfwSetKeyCallback (window, key_func);
   glfwSetCharCallback (window, char_func);
   glfwSetMouseButtonCallback (window, mouse_func);
   glfwSetScrollCallback (window, scroll_func);
   glfwSetCursorPosCallback (window, cursor_func);

   {
     int fb_width, fb_height;
     glfwGetFramebufferSize (window, &fb_width, &fb_height);
     glViewport (0, 0, fb_width, fb_height);
   }

   renderer = demo_renderer_create_gl (window);
   vu = demo_view_create (renderer, window);

   current_blob = hb_blob_create ((const char *) default_font,
 				 sizeof (default_font),
 				 HB_MEMORY_MODE_READONLY,
 				 NULL, NULL);
   current_face = hb_face_create (current_blob, 0);
   current_font = hb_font_create (current_face);
   current_demo_font = demo_font_create (current_font, renderer->get_atlas ());

   current_text = strdup (default_text_combined);

   buffer = demo_buffer_create ();
   demo_point_t top_left = {0, 0};
   demo_buffer_move_to (buffer, &top_left);
   demo_buffer_add_text (buffer, current_text, current_demo_font, 1);

   demo_font_print_stats (current_demo_font);

   demo_view_setup (vu);

   emscripten_set_main_loop (main_loop_iter, 0, 1);

   /* Not reached */
   return 0;
 }
	/*
	* Copyright (C) 2026 Behdad Esfahbod
	*
	* This is part of HarfBuzz, a text shaping library.
	*
	* Permission is hereby granted, without written agreement and without
	* license or royalty fees, to use, copy, modify, and distribute this
	* software and its documentation for any purpose, provided that the
	* above copyright notice and the following two paragraphs appear in
	* all copies of this software.
	*
	* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
	* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
	* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
	*
	* Author(s): Behdad Esfahbod
	*/

	/*
	* Web (Emscripten) build of the hb-gpu demo.
	*
	* Reuses the desktop demo code with two changes:
	* 1. emscripten_set_main_loop replaces the blocking while loop
	* 2. HB_GPU_ATLAS_2D is defined (WebGL2 lacks texture buffers)
	*
	* Build:
	* source emsdk/emsdk_env.sh
	* ./util/gpu/web/build.sh
	*
	* Serve:
	* python3 -m http.server -d util/gpu/web/out
	*/

	#include <emscripten.h>
	#include <emscripten/html5.h>

	/* Pull in the demo code — all headers are self-contained */
	#include "../demo-common.h"
	#include "../demo-buffer.h"
	#include "../demo-font.h"
	#include "../demo-renderer.h"
	#include "../demo-view.h"

	#include "../default-text-combined.hh"
	#include "../default-text-en.hh"
	#include "../default-font.hh"

	static demo_renderer_t *renderer;
	static demo_view_t *vu;
	static demo_buffer_t *buffer;
	static demo_font_t *current_demo_font;
	static hb_blob_t *current_blob;
	static hb_face_t *current_face;
	static hb_font_t *current_font;
	static char *current_text;
	static bool custom_text;

	static void
	rebuild_buffer (const char *text)
	{
	free (current_text);
	current_text = strdup (text);

	demo_font_clear_cache (current_demo_font);
	demo_atlas_clear (renderer->get_atlas ());

	demo_buffer_clear (buffer);
	demo_point_t top_left = {0, 0};
	demo_buffer_move_to (buffer, &top_left);
	demo_buffer_add_text (buffer, text, current_demo_font, 1);
	demo_view_reset (vu);
	demo_view_display (vu, buffer);
	}

	extern "C" {

	EMSCRIPTEN_KEEPALIVE void
	web_load_font (const char *data, int len)
	{
	hb_blob_t *blob = hb_blob_create (data, len,
	HB_MEMORY_MODE_DUPLICATE,
	NULL, NULL);
	hb_face_t *face = hb_face_create (blob, 0);
	hb_font_t *font = hb_font_create (face);

	hb_blob_destroy (current_blob);
	hb_face_destroy (current_face);
	hb_font_destroy (current_font);

	current_blob = blob;
	current_face = face;
	current_font = font;

	/* Flush old font state */
	demo_font_destroy (current_demo_font);
	current_demo_font = demo_font_create (font, renderer->get_atlas ());

	rebuild_buffer (custom_text ? current_text : default_text_en);
	demo_font_print_stats (current_demo_font);
	}

	EMSCRIPTEN_KEEPALIVE void
	web_set_text (const char *utf8)
	{
	custom_text = true;
	rebuild_buffer (utf8);
	}

	EMSCRIPTEN_KEEPALIVE const char *
	web_get_text ()
	{
	return current_text;
	}

	EMSCRIPTEN_KEEPALIVE void
	web_toggle_animation ()
	{
	demo_view_key_func (vu, 32 /* GLFW_KEY_SPACE */, 0, 1, 0);
	}

	EMSCRIPTEN_KEEPALIVE void
	web_reset ()
	{
	demo_view_reset (vu);
	}

	EMSCRIPTEN_KEEPALIVE void
	web_request_redraw ()
	{
	demo_view_request_redraw (vu);
	}

	EMSCRIPTEN_KEEPALIVE void
	web_cancel_gesture ()
	{
	demo_view_cancel_gesture (vu);
	}

	EMSCRIPTEN_KEEPALIVE void
	web_pinch (float pan_dx, float pan_dy,
	float zoom_factor, float angle_delta,
	float cx, float cy, int w, int h)
	{
	demo_view_pinch (vu, pan_dx, pan_dy, zoom_factor, angle_delta, cx, cy, w, h);
	}

	} /* extern "C" */

	static void
	main_loop_iter ()
	{
	glfwPollEvents ();

	if (demo_view_should_redraw (vu))
	demo_view_display (vu, buffer);
	}

	static void
	framebuffer_size_func (GLFWwindow *window, int width, int height)
	{ demo_view_reshape_func (vu, width, height); }

	static void
	key_func (GLFWwindow *window, int key, int scancode, int action, int mods)
	{ demo_view_key_func (vu, key, scancode, action, mods); }

	static void
	char_func (GLFWwindow *window, unsigned int codepoint)
	{ demo_view_char_func (vu, codepoint); }

	static void
	mouse_func (GLFWwindow *window, int button, int action, int mods)
	{ demo_view_mouse_func (vu, button, action, mods); }

	static void
	scroll_func (GLFWwindow *window, double xoffset, double yoffset)
	{ demo_view_scroll_func (vu, xoffset, yoffset); }

	static void
	cursor_func (GLFWwindow *window, double x, double y)
	{ demo_view_motion_func (vu, x, y); }

	int
	main ()
	{
	if (!glfwInit ())
	{
	fprintf (stderr, "Failed to initialize GLFW\n");
	return 1;
	}

	glfwWindowHint (GLFW_CONTEXT_VERSION_MAJOR, 3);
	glfwWindowHint (GLFW_CONTEXT_VERSION_MINOR, 0);
	glfwWindowHint (GLFW_CLIENT_API, GLFW_OPENGL_ES_API);

	/* Query actual canvas size from the browser. */
	int canvas_w = 700, canvas_h = 700;
	emscripten_get_canvas_element_size ("#canvas", &canvas_w, &canvas_h);

	GLFWwindow *window = glfwCreateWindow (canvas_w, canvas_h, "HarfBuzz GPU Demo", NULL, NULL);
	if (!window)
	{
	glfwTerminate ();
	fprintf (stderr, "Failed to create GLFW window\n");
	return 1;
	}
	glfwMakeContextCurrent (window);

	glfwSetFramebufferSizeCallback (window, framebuffer_size_func);
	glfwSetKeyCallback (window, key_func);
	glfwSetCharCallback (window, char_func);
	glfwSetMouseButtonCallback (window, mouse_func);
	glfwSetScrollCallback (window, scroll_func);
	glfwSetCursorPosCallback (window, cursor_func);

	{
	int fb_width, fb_height;
	glfwGetFramebufferSize (window, &fb_width, &fb_height);
	glViewport (0, 0, fb_width, fb_height);
	}

	renderer = demo_renderer_create_gl (window);
	vu = demo_view_create (renderer, window);

	current_blob = hb_blob_create ((const char *) default_font,
	sizeof (default_font),
	HB_MEMORY_MODE_READONLY,
	NULL, NULL);
	current_face = hb_face_create (current_blob, 0);
	current_font = hb_font_create (current_face);
	current_demo_font = demo_font_create (current_font, renderer->get_atlas ());

	current_text = strdup (default_text_combined);

	buffer = demo_buffer_create ();
	demo_point_t top_left = {0, 0};
	demo_buffer_move_to (buffer, &top_left);
	demo_buffer_add_text (buffer, current_text, current_demo_font, 1);

	demo_font_print_stats (current_demo_font);

	demo_view_setup (vu);

	emscripten_set_main_loop (main_loop_iter, 0, 1);

	/* Not reached */
	return 0;
	}