From b39f418bca9d0421eca127a11a0fb65bd2c37459 Mon Sep 17 00:00:00 2001
From: Daniel Silverstone <dsilvers@digital-scurf.org>
Date: Fri, 22 May 2020 15:59:47 +0100
Subject: [PATCH] html: Add canvas node handling in dom_event

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>
---
 content/handlers/html/dom_event.c | 133 ++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)

diff --git a/content/handlers/html/dom_event.c b/content/handlers/html/dom_event.c
index b702cb304..5470f2942 100644
--- a/content/handlers/html/dom_event.c
+++ b/content/handlers/html/dom_event.c
@@ -32,6 +32,10 @@
 #include "content/content.h"
 #include "javascript/js.h"
 
+#include "desktop/gui_internal.h"
+#include "desktop/gui_table.h"
+#include "netsurf/bitmap.h"
+
 #include "html/private.h"
 #include "html/object.h"
 #include "html/css.h"
@@ -102,6 +106,69 @@ static bool html_process_inserted_base(html_content *htmlc, dom_node *node)
 	return true;
 }
 
+/**
+ * deal with events from the DOM for canvas node user data
+ *
+ * \param operation The DOM operation happening
+ * \param key The user data key
+ * \param data The user data (our bitmap)
+ * \param src The DOM node emitting the event (our <canvas>)
+ * \param dst The target DOM node if applicable
+ */
+static void
+html__canvas_user_data_handler(dom_node_operation operation,
+			       dom_string *key,
+			       void *data,
+			       struct dom_node *src,
+			       struct dom_node *dst)
+{
+	struct bitmap *newbitmap, *bitmap = (struct bitmap*)data, *oldbitmap = NULL;
+	int width, height;
+	size_t stride;
+
+	if (dom_string_isequal(key,corestring_dom___ns_key_canvas_node_data) == false || data == NULL) {
+		/* Not for us */
+		return;
+	}
+
+	switch (operation) {
+	case DOM_NODE_CLONED:
+		width = guit->bitmap->get_width(bitmap);
+		height = guit->bitmap->get_height(bitmap);
+		stride = guit->bitmap->get_rowstride(bitmap);
+		newbitmap = guit->bitmap->create(width, height,
+						 BITMAP_NEW);
+		if (newbitmap != NULL) {
+			if (guit->bitmap->get_rowstride(newbitmap) == stride) {
+				// Compatible bitmap, bung the data over
+				memcpy(guit->bitmap->get_buffer(newbitmap),
+				       guit->bitmap->get_buffer(bitmap),
+				       stride * height);
+				guit->bitmap->modified(newbitmap);
+			}
+		}
+		if (dom_node_set_user_data(dst,
+					   corestring_dom___ns_key_canvas_node_data,
+					   newbitmap, html__canvas_user_data_handler,
+					   &oldbitmap) == DOM_NO_ERR) {
+			if (oldbitmap != NULL)
+				guit->bitmap->destroy(oldbitmap);
+		}
+		break;
+
+	case DOM_NODE_RENAMED:
+	case DOM_NODE_IMPORTED:
+	case DOM_NODE_ADOPTED:
+		break;
+
+	case DOM_NODE_DELETED:
+		guit->bitmap->destroy(bitmap);
+		break;
+	default:
+		NSLOG(netsurf, INFO, "User data operation not handled.");
+		assert(0);
+	}
+}
 
 /**
  * process a canvas element being inserted into the DOM
@@ -112,6 +179,72 @@ static bool html_process_inserted_base(html_content *htmlc, dom_node *node)
  */
 static nserror html_process_inserted_canvas(html_content *htmlc, dom_node *node)
 {
+	dom_exception exc;
+	dom_string *width_s = NULL, *height_s = NULL;
+	unsigned long width = 300, height = 150;
+	struct bitmap *bitmap, *oldbitmap = NULL;
+
+	exc = dom_element_get_attribute(node,
+					corestring_dom_width,
+					&width_s);
+	if (exc == DOM_NO_ERR && width_s != NULL) {
+		const char *ptr = (const char *)dom_string_data(width_s);
+		const char *endptr = ptr + dom_string_length(width_s);
+		char * ended;
+		unsigned long width_n = strtoul(ptr, &ended, 10);
+
+		if (ended == endptr) {
+			/* parsed it all */
+			width = width_n;
+		}
+
+		dom_string_unref(width_s);
+	}
+
+	exc = dom_element_get_attribute(node,
+					corestring_dom_height,
+					&height_s);
+	if (exc == DOM_NO_ERR && height_s != NULL) {
+		const char *ptr = (const char *)dom_string_data(height_s);
+		const char *endptr = ptr + dom_string_length(height_s);
+		char * ended;
+		unsigned long height_n = strtoul(ptr, &ended, 10);
+
+		if (ended == endptr) {
+			/* parsed it all */
+			height = height_n;
+		}
+
+		dom_string_unref(height_s);
+	}
+
+	bitmap = guit->bitmap->create(
+		(int)width, (int)height,
+		BITMAP_NEW);
+
+	if (bitmap == NULL) {
+		return NSERROR_NOMEM;
+	}
+
+	memset(guit->bitmap->get_buffer(bitmap),
+	       0, /* Transparent black */
+	       height * guit->bitmap->get_rowstride(bitmap));
+	guit->bitmap->modified(bitmap);
+
+	exc = dom_node_set_user_data(node,
+				     corestring_dom___ns_key_canvas_node_data,
+				     bitmap,
+				     html__canvas_user_data_handler,
+				     &oldbitmap);
+
+	if (exc != DOM_NO_ERR) {
+		guit->bitmap->destroy(bitmap);
+		return NSERROR_DOM;
+	}
+
+	if (oldbitmap != NULL)
+		guit->bitmap->destroy(oldbitmap);
+
 	return NSERROR_OK;
 }