Animating gradient displays line artifacts in ActionScript
- by TheDarkIn1978
i've programatically created a simple gradient (blue to red) sprite rect using my own basic class called GradientRect, but moving or animation the sprite exhibits line artifacts. when the sprite is rotating, it kind of resembles bad reception of an old television set.
i'm almost certain the cause is because each line slice of the gradient is vector so there are gaps between the lines - this is visible when the sprite is zoomed in.
var colorPickerRect:GradientRect = new GradientRect(200, 200, 0x0000FF, 0xFF0000);
addChild(colorPickerRect);
colorPickerRect.cacheAsBitmap = true;
colorPickerRect.x = colorPickerRect.y = 100;
colorPickerRect.addEventListener(Event.ENTER_FRAME, rotate);
function rotate(evt:Event):void
{
evt.target.rotation += 1;
}
________________________
//CLASS PACKAGE
package
{
import flash.display.CapsStyle;
import flash.display.GradientType;
import flash.display.LineScaleMode;
import flash.display.Sprite;
import flash.geom.Matrix;
public class GradientRect extends Sprite
{
public function GradientRect(gradientRectWidth:Number, gradientRectHeight:Number, ...leftToRightColors)
{
init(gradientRectWidth, gradientRectHeight, leftToRightColors);
}
private function init(gradientRectWidth:Number, gradientRectHeight:Number, leftToRightColors:Array):void
{
var leftToRightAlphas:Array = new Array();
var leftToRightRatios:Array = new Array();
var leftToRightPartition:Number = 255 / (leftToRightColors.length - 1);
var pixelColor:Number;
var i:int;
//Push arrays
for (i = 0; i < leftToRightColors.length; i++)
{
leftToRightAlphas.push(1);
leftToRightRatios.push(i * leftToRightPartition);
}
//Graphics matrix and lineStyle
var leftToRightColorsMatrix:Matrix = new Matrix();
leftToRightColorsMatrix.createGradientBox(gradientRectWidth, 1);
graphics.lineStyle(1, 0, 1, false, LineScaleMode.NONE, CapsStyle.NONE);
for (i = 0; i < gradientRectWidth; i++)
{
graphics.lineGradientStyle(GradientType.LINEAR, leftToRightColors, leftToRightAlphas, leftToRightRatios, leftToRightColorsMatrix);
graphics.moveTo(i, 0);
graphics.lineTo(i, gradientRectHeight);
}
}
}
}
how can i solve this problem?
