Referencia de lienzo HTML
Descripción
La etiqueta HTML5 <canvas> se usa para dibujar gráficos, sobre la marcha, a través de scripts (generalmente JavaScript).
Sin embargo, el elemento <canvas> no tiene capacidades de dibujo propias (solo es un contenedor para gráficos); debe usar un script para dibujar los gráficos.
El método getContext () devuelve un objeto que proporciona métodos y propiedades para dibujar en el lienzo.
Esta referencia cubrirá las propiedades y métodos del objeto getContext ("2d"), que se puede usar para dibujar texto, líneas, recuadros, círculos y más, en el lienzo.
Soporte del navegador
Los números en la tabla especifican la primera versión del navegador que admite completamente el elemento.
| Element | | | | | |
| <canvas> | 4.0 | 9.0 | 2.0 | 3.1 | 9.0 |
Internet Explorer 9, Firefox, Opera, Chrome y Safari admiten <canvas> y sus propiedades y métodos.
Nota: Internet Explorer 8 y versiones anteriores no son compatibles con el elemento <canvas>.
Colores, estilos y sombras
| Property | Description |
| fillStyle | Sets or returns the color, gradient, or pattern used to fill the drawing |
| strokeStyle | Sets or returns the color, gradient, or pattern used for strokes |
| shadowColor | Sets or returns the color to use for shadows |
| shadowBlur | Sets or returns the blur level for shadows |
| shadowOffsetX | Sets or returns the horizontal distance of the shadow from the shape |
| shadowOffsetY | Sets or returns the vertical distance of the shadow from the shape |
Estilos de línea
| Property | Description |
| lineCap | Sets or returns the style of the end caps for a line |
| lineJoin | Sets or returns the type of corner created, when two lines meet |
| lineWidth | Sets or returns the current line width |
| miterLimit | Sets or returns the maximum miter length |
Rectángulos
Caminos
| Method | Description |
| fill() | Fills the current drawing (path) |
| stroke() | Actually draws the path you have defined |
| beginPath() | Begins a path, or resets the current path |
| moveTo() | Moves the path to the specified point in the canvas, without creating a line |
| closePath() | Creates a path from the current point back to the starting point |
| lineTo() | Adds a new point and creates a line to that point from the last specified point in the canvas |
| clip() | Clips a region of any shape and size from the original canvas |
| quadraticCurveTo() | Creates a quadratic Bézier curve |
| bezierCurveTo() | Creates a cubic Bézier curve |
| arc() | Creates an arc/curve (used to create circles, or parts of circles) |
| arcTo() | Creates an arc/curve between two tangents |
| isPointInPath() | Returns true if the specified point is in the current path, otherwise false |
Transformaciones
| Method | Description |
| scale() | Scales the current drawing bigger or smaller |
| rotate() | Rotates the current drawing |
| translate() | Remaps the (0,0) position on the canvas |
| transform() | Replaces the current transformation matrix for the drawing |
| setTransform() | Resets the current transform to the identity matrix. Then runs transform() |
Texto
| Property | Description |
| font | Sets or returns the current font properties for text content |
| textAlign | Sets or returns the current alignment for text content |
| textBaseline | Sets or returns the current text baseline used when drawing text |
| Method | Description |
| fillText() | Draws "filled" text on the canvas |
| strokeText() | Draws text on the canvas (no fill) |
| measureText() | Returns an object that contains the width of the specified text |
Dibujo de la imagen
| Method | Description |
| drawImage() | Draws an image, canvas, or video onto the canvas |
Manipulación de píxeles
| Property | Description |
| width | Returns the width of an ImageData object |
| height | Returns the height of an ImageData object |
| data | Returns an object that contains image data of a specified ImageData object |
| Method | Description |
| createImageData() | Creates a new, blank ImageData object |
| getImageData() | Returns an ImageData object that copies the pixel data for the specified rectangle on a canvas |
| putImageData() | Puts the image data (from a specified ImageData object) back onto the canvas |
Compositing
| Property | Description |
| globalAlpha | Sets or returns the current alpha or transparency value of the drawing |
| globalCompositeOperation | Sets or returns how a new image are drawn onto an existing image |
Otro
| Method | Description |
| save() | Saves the state of the current context |
| restore() | Returns previously saved path state and attributes |
| createEvent() | |
| getContext() | |
| toDataURL() | |