{
"domain": "Canvas",
"availability": "web",
"description": "Canvas domain allows tracking of canvases that have an associated graphics context. Tracks canvases in the DOM and CSS canvases created with -webkit-canvas.",
"types": [
{
"id": "CanvasId",
"type": "string",
"description": "Unique canvas identifier."
},
{
"id": "ContextType",
"type": "string",
"enum": ["canvas-2d", "webgl", "webgl2", "webgpu"],
"description": "The type of rendering context backing the canvas element."
},
{
"id": "ContextAttributes",
"type": "object",
"description": "WebGL drawing surface attributes.",
"properties": [
{ "name": "alpha", "type": "boolean" },
{ "name": "depth", "type": "boolean" },
{ "name": "stencil", "type": "boolean" },
{ "name": "antialias", "type": "boolean" },
{ "name": "premultipliedAlpha", "type": "boolean" },
{ "name": "preserveDrawingBuffer", "type": "boolean" },
{ "name": "failIfMajorPerformanceCaveat", "type": "boolean" }
]
},
{
"id": "Canvas",
"type": "object",
"description": "Information about a canvas for which a rendering context has been created.",
"properties": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Canvas identifier." },
{ "name": "contextType", "$ref": "ContextType", "description": "The type of rendering context backing the canvas." },
{ "name": "frameId", "$ref": "Network.FrameId", "description": "Parent frame identifier." },
{ "name": "nodeId", "$ref": "DOM.NodeId", "optional": true, "description": "The corresponding DOM node id." },
{ "name": "cssCanvasName", "type": "string", "optional": true, "description": "The CSS canvas identifier, for canvases created with <code>document.getCSSCanvasContext</code>." },
{ "name": "contextAttributes", "$ref": "ContextAttributes", "optional": true, "description": "Context attributes for WebGL rendering contexts." },
{ "name": "memoryCost", "type": "number", "optional": true, "description": "Memory usage of the canvas in bytes." }
]
}
],
"commands": [
{
"name": "enable",
"description": "Enables Canvas domain events."
},
{
"name": "disable",
"description": "Disables Canvas domain events."
},
{
"name": "requestNode",
"description": "Gets the NodeId for the canvas node with the given CanvasId.",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Canvas identifier." }
],
"returns": [
{ "name": "nodeId", "$ref": "DOM.NodeId", "description": "Node identifier for given canvas." }
]
},
{
"name": "requestContent",
"description": "Gets the data for the canvas node with the given CanvasId.",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Canvas identifier." }
],
"returns": [
{ "name": "content", "type": "string", "description": "Base64-encoded data of the canvas' contents." }
]
},
{
"name": "requestCSSCanvasClientNodes",
"description": "Gets all the nodes that are using this canvas via -webkit-canvas.",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId" }
],
"returns": [
{ "name": "clientNodeIds", "type": "array", "items": { "$ref": "DOM.NodeId" } }
]
},
{
"name": "resolveCanvasContext",
"description": "Resolves JavaScript canvas context object for given canvasId.",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Canvas identifier." },
{ "name": "objectGroup", "type": "string", "optional": true, "description": "Symbolic group name that can be used to release multiple objects." }
],
"returns": [
{ "name": "object", "$ref": "Runtime.RemoteObject", "description": "JavaScript object wrapper for given canvas context." }
]
}
],
"events": [
{
"name": "canvasAdded",
"parameters": [
{ "name": "canvas", "$ref": "Canvas", "description": "Canvas object." }
]
},
{
"name": "canvasRemoved",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Removed canvas identifier." }
]
},
{
"name": "canvasMemoryChanged",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Identifier of canvas that changed." },
{ "name": "memoryCost", "type": "number", "description": "New memory cost value for the canvas in bytes." }
]
},
{
"name": "cssCanvasClientNodesChanged",
"parameters": [
{ "name": "canvasId", "$ref": "CanvasId", "description": "Identifier of canvas that changed." }
]
}
]
}