What functions and APIs does canvas have?

Canvas functions and APIs include drawing shapes, drawing text, image processing, gradients and shadows, animation effects, pixel-level operations, event handling, transformation and translation, composition and mixing, pixel ratio, clearing and redrawing, etc. . Detailed introduction: 1. Draw shapes. Canvas provides APIs for drawing basic shapes, such as drawing rectangles, circles, lines, paths, etc.; 2. Draw text. Canvas can draw text and set font, size, color and other styles; 3. , image processing, etc.

The operating environment of this tutorial: Windows system, Dell G3 computer.

Canvas has rich functions and APIs. The following are some commonly used functions and APIs:

1. Drawing shapes: Canvas provides drawing basic shapes API, such as drawing rectangles, circles, lines, paths, etc.

2. Draw text: Canvas can draw text and set font, size, color and other styles.

3. Image processing: Canvas can load and draw images, and can perform operations such as cropping, rotation, and scaling.

4. Gradient and shadow: Canvas supports gradient and shadow effects, and can create linear gradients, radial gradients and shadow effects.

5. Animation effect: Canvas animation effect can be achieved by using a timer (such as setInterval or requestAnimationFrame) and updating the graphics on the canvas.

6. Pixel-level operations: Canvas provides pixel-level operations, which can read and modify pixel data on the canvas.

7. Event processing: Canvas can handle events such as mouse clicks and movements. You can use the addEventListener method to add event listeners and perform corresponding operations when the event is triggered.

8. Transformation and translation: Canvas supports transformation and translation operations on drawings, such as rotation, scaling, translation, etc.

9. Synthesis and mixing: Canvas can achieve the synthesis and mixing effects of different graphics by setting the globalCompositeOperation property.

10. Pixel ratio: Canvas provides properties and methods related to device pixel ratio, which can handle drawing problems on high-resolution screens.

11. Clear and redraw: Canvas provides the clearRect method to clear the content on the canvas, and the canvas can be redrawn by redrawing the graphics.

The above are some commonly used Canvas functions and APIs. By flexibly using these functions and APIs, various complex drawings, animations and interactive effects can be achieved.

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