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我正在开发一个应用程序，它必须在纵向iPhone屏幕上绘制320条垂直渐变线，其中每个渐变线的宽度为1px或2px（非视网膜vs视网膜）。每个渐变线都有1000个位置，每个位置都有唯一的颜色。这1000种颜色（花车）坐在C风格的2D阵列（阵列阵列，1000个颜色的320阵列）如何快速绘制许多渐变线
目前，渐变线绘制在自定义UIView的drawRect方法内的For循环中。我遇到的问题是花费比一秒多的时间循环遍历For循环并绘制全部320行。在那一秒钟内，我有另一个更新颜色数组的线程，但由于它需要一秒以上的绘制时间，我没有看到每一个更新。我看到每第二次或第三次更新。
我使用在我的Android代码，它没有问题绘图640条梯度线完全相同的过程中多次的第二使用SurfaceView（两倍的量）。我的Android应用程序永远不会错过任何更新。
如果您看一下Android代码，它实际上会为两个单独的画布绘制渐变线。数组大小是动态的，可以达到Android手机的横向分辨率宽度的一半（例如1280宽度= 1280/2 = 640行）。由于Android应用足够快，我允许横向模式。即使将数据翻倍为iPhone并绘制到两个单独的画布上，Android代码也会每秒运行多次。具有一半行数的iPhone代码只能绘制到单个上下文中，不能在一秒之内完成。
是否有更快的方式在iPhone上绘制320条垂直渐变线（每个线都有1000个位置）？
是否有硬件加速SurfaceView等价物，可以吸引很多梯度非常快的iOS？
//IPHONE - drawRect method
int totalNumberOfColors = 1000;
int i;
CGFloat *locations = malloc(totalNumberOfColors * sizeof locations[0]);
for (i = 0; i < totalNumberOfColors; i++) {
float division = (float)1/(float)(totalNumberOfColors - 1);
locations[i] = i * division;
}
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
for (int k = 0; k < 320; k++) {
CGFloat * colorComponents = arrayOfFloatArrays[k];
CGGradientRef gradient = CGGradientCreateWithColorComponents(
colorSpace,
colorComponents,
locations,
(size_t)(totalNumberOfColors));
CGRect newRect;
if (currentPositionOffset >=320) {
newRect = CGRectMake(0, 0, 1, CGRectGetMaxY(rect));
} else {
newRect = CGRectMake(319 - (k * 1), 0, 1, CGRectGetMaxY(rect));
}
CGContextSaveGState(ctx);
//NO CLIPPING STATE
CGContextAddRect(ctx, newRect);
CGContextClip(ctx);
//CLIPPING STATE
CGContextDrawLinearGradient(
ctx,
gradient,
CGPointMake(0, 0),
CGPointMake(0, CGRectGetMaxY(rect)),
(CGGradientDrawingOptions)NULL);
CGContextRestoreGState(ctx);
//RESTORE TO NO CLIPPING STATE
CGGradientRelease(gradient);
}
//ANDROID - public void run() method on SurfaceView
for (i = 0; i < sonarData.arrayOfColorIntColumns.size() - currentPositionOffset; i++) {
Paint paint = new Paint();
int[] currentColors = sonarData.arrayOfColorIntColumns.get(currentPositionOffset + i);
//Log.d("currentColors.toString()",currentColors.toString());
LinearGradient linearGradient;
if (currentScaleFactor > 1.0) {
int numberOfColorsToUse = (int)(1000.0/currentScaleFactor);
int tmpTopOffset = currentTopOffset;
if (currentTopOffset + numberOfColorsToUse > 1000) {
//shift tmpTopOffset
tmpTopOffset = 1000 - numberOfColorsToUse - 1;
}
int[] subsetOfCurrentColors = new int[numberOfColorsToUse];
System.arraycopy(currentColors, tmpTopOffset, subsetOfCurrentColors, 0, numberOfColorsToUse);
linearGradient = new LinearGradient(0, tmpTopOffset, 0, getHeight(), subsetOfCurrentColors, null, Shader.TileMode.MIRROR);
//Log.d("getHeight()","" + getHeight());
//Log.d("subsetOfCurrentColors.length","" + subsetOfCurrentColors.length);
} else {
//use all colors
linearGradient = new LinearGradient(0, 0, 0, getHeight(), currentColors, null, Shader.TileMode.MIRROR);
//Log.d("getHeight()","" + getHeight());
//Log.d("currentColors.length","" + currentColors.length);
}
paint.setShader(linearGradient);
sonarData.checkAndAddPaint(paint);
numberOfColumnsToDraw = i + 1;
}
//Log.d(TAG,"numberOfColumnsToDraw " + numberOfColumnsToDraw);
currentPositionOffset = currentPositionOffset + i;
if (currentPositionOffset >= sonarData.getMaxNumberOfColumns()) {
currentPositionOffset = sonarData.getMaxNumberOfColumns() - 1;
}
if (numberOfColumnsToDraw > 0) {
Canvas canvas = surfaceHolder.lockCanvas();
if (AppInstanceData.sonarBackgroundImage != null && canvas != null) {
canvas.drawBitmap(AppInstanceData.sonarBackgroundImage, 0, getHeight()- AppInstanceData.sonarBackgroundImage.getHeight(), null);
if (cacheCanvas != null) {
cacheCanvas.drawBitmap(AppInstanceData.sonarBackgroundImage, 0, getHeight()- AppInstanceData.sonarBackgroundImage.getHeight(), null);
}
}
for (i = drawOffset; i < sizeToDraw + drawOffset; i++) {
Paint p = sonarData.paintArray.get(i - dataStartOffset);
p.setStrokeWidth(2);
//Log.d("drawGradientLines", "canvas.getHeight() " + canvas.getHeight());
canvas.drawLine(getWidth() - (i - drawOffset) * 2, 0, getWidth() - (i - drawOffset) * 2, canvas.getHeight(), p);
if (cacheCanvas != null) {
cacheCanvas.drawLine(getWidth() - (i - drawOffset) * 2, 0, getWidth() - (i - drawOffset) * 2, canvas.getHeight(), p);
}
}
surfaceHolder.unlockCanvasAndPost(canvas);
}