API Reference: Paint

The Paint class defines the style, color, and effects used when drawing on a Canvas. It is a lightweight object that can be reused across multiple drawing calls.

Core Properties

Color and Transparency

• setColor(int color): Sets the ARGB color.
• setAlpha(int alpha): Sets only the alpha (transparency) component (0-255).
• setColor4f(Color4f color, ColorSpace space): Sets the color using floating-point values for higher precision.

Style

• setMode(PaintMode mode): Determines if the paint fills the interior of a shape (FILL), strokes the outline (STROKE), or both (STROKE_AND_FILL).
• setStrokeWidth(float width): Sets the thickness of the stroke.
• setStrokeCap(PaintStrokeCap cap): Defines the shape of the ends of a stroked line (BUTT, ROUND, SQUARE).
• setStrokeJoin(PaintStrokeJoin join): Defines how stroked segments are joined (MITER, ROUND, BEVEL).

Anti-aliasing

• setAntiAlias(boolean enabled): Enables or disables edge smoothing. Highly recommended for most UI drawing.

Effects and Shaders

Paint objects can be enhanced with various effects to create complex visuals.

Shaders (Gradients and Patterns)

Shaders define the color of each pixel based on its position.

• setShader(Shader shader): Applies a linear gradient, radial gradient, or image pattern.

Color Filters

Color filters modify the colors of the source before they are drawn.

• setColorFilter(ColorFilter filter): Applies color matrices, blend modes, or luma transformations.

Mask Filters (Blurs)

Mask filters affect the alpha channel of the drawing.

• setMaskFilter(MaskFilter filter): Used primarily for creating blurs and shadows.

Image Filters

Image filters are more complex and can affect the entire drawing result.

• setImageFilter(ImageFilter filter): Used for blurs, dropshadows, and combining multiple effects.

Usage Example

Paint paint = new Paint()
    .setColor(0xFF4285F4)
    .setAntiAlias(true)
    .setMode(PaintMode.STROKE)
    .setStrokeWidth(4f)
    .setStrokeJoin(PaintStrokeJoin.ROUND);

canvas.drawRect(Rect.makeXYWH(10, 10, 100, 100), paint);

Performance Note

Creating a Paint object is relatively fast, but modifying it frequently in a tight loop can have some overhead. It is generally recommended to prepare your Paint objects once and reuse them during rendering if their properties don't change.