Class LinearGradient

java.lang.Object

com.codename1.ui.Gradient

com.codename1.ui.LinearGradient

All Implemented Interfaces:

Paint

public final class LinearGradient
extends Gradient

Multi-stop linear gradient at an arbitrary angle. Mirrors CSS linear-gradient(<angle>, <stops>). Angle is in CSS degrees: 0 points up (toward the top edge), 90 right, 180 down, 270 left.

Field Summary

Fields inherited from class Gradient

CYCLE_NONE, CYCLE_REFLECT, CYCLE_REPEAT, KIND_CONIC, KIND_LINEAR, KIND_RADIAL

Constructor Summary

Constructors

Constructor	Description
LinearGradient(float angleDegrees, int[] colors, float[] positions)	Creates a linear gradient at the given angle with the given stops.

Method Summary

Modifier and Type	Method	Description
void	computeEndpoints(int width, int height, float[] out)	Computes the endpoints of the gradient line for a rectangle of the given width / height (rect origin at (0,0)).
void	computeShaderEndpoints(int width, int height, float[] out)	Computes shader-ready endpoints for native APIs like Android's LinearGradient and Java2D's LinearGradientPaint.
LinearGradient	copy()	Returns a defensive deep copy.
float	getAngleDegrees()
byte	getKind()	Returns one of KIND_LINEAR, KIND_RADIAL, KIND_CONIC.
float[]	getNormalizedPositions()	Returns stop positions rescaled to [0, 1] within the [first_stop, last_stop] range of the original positions.
int	sampleArgb(int px, int py, int width, int height)	Software-rasterizer hook used by the default port implementation when no native gradient shader is available.
LinearGradient	setAngleDegrees(float angleDegrees)

Methods inherited from class Gradient

getCachedRaster, getColors, getCycleMethod, getPositions, invalidateRasterCache, paint, paint, parseCss, sampleStops, setCycleMethod

Methods inherited from class Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LinearGradient

public LinearGradient(float angleDegrees,
 int[] colors,
 float[] positions)

Creates a linear gradient at the given angle with the given stops.

Method Details

getKind

public byte getKind()

Description copied from class: Gradient

Returns one of KIND_LINEAR, KIND_RADIAL, KIND_CONIC.

Specified by:

getKind in class Gradient

getAngleDegrees

public float getAngleDegrees()

setAngleDegrees

public LinearGradient setAngleDegrees(float angleDegrees)

computeEndpoints

public void computeEndpoints(int width,
 int height,
 float[] out)

Computes the endpoints of the gradient line for a rectangle of the given width / height (rect origin at (0,0)). Output is x0,y0,x1,y1. These endpoints span the full bounding box; stop positions are interpreted relative to them.

computeShaderEndpoints

public void computeShaderEndpoints(int width,
 int height,
 float[] out)

Computes shader-ready endpoints for native APIs like Android's LinearGradient and Java2D's LinearGradientPaint. For NO_CYCLE this is the same as computeEndpoints. For REPEAT / REFLECT it clips the endpoint range to span exactly one stop-list period (from getPositions()[0] to getPositions()[N-1] of the original line) so the native shader's tile mode wraps the period across the rest of the bounding box - matching the CSS repeating-linear-gradient semantic.

Use getNormalizedPositions() for the matching stop array when using these endpoints with REPEAT/REFLECT.

getNormalizedPositions

public float[] getNormalizedPositions()

Returns stop positions rescaled to [0, 1] within the [first_stop, last_stop] range of the original positions. For NO_CYCLE this is the same as getPositions(); for REPEAT/REFLECT it is the array to pass alongside computeShaderEndpoints.

sampleArgb

public int sampleArgb(int px,
 int py,
 int width,
 int height)

Description copied from class: Gradient

Software-rasterizer hook used by the default port implementation when no native gradient shader is available. Samples an ARGB color for the pixel at (px, py) within a rectangle of the given width / height. Ports overriding fillGradient directly do not call this.

Specified by:

sampleArgb in class Gradient

copy

public LinearGradient copy()

Description copied from class: Gradient

Returns a defensive deep copy. Implemented by each concrete subclass so async-paint queues can capture an immutable snapshot.

Specified by:

copy in class Gradient