Android canvas setShadowLayer 大大降低性能

发布于 2024-12-25 06:46:34 字数 292 浏览 3 评论 0原文

我正在 Android 上编写一个画布应用程序，并且希望添加阴影，但是当我将它们添加到绘画对象时，我注意到速度明显变慢。我的代码很简单，如下所示：

...
Paint paint = new Paint();
paint.setShadowLayer(8.f, 0, 0, 0xff000000); // this line makes terribly slow drawing
canvas.drawRect(left, top, right, bottom, paint);

我怎样才能使它更快？

原文

I'm writing a canvas app on android and I'm looking to add shadows, but I've noticed a great slow-down when I add them to my paint object. My code is simple it looks like this:

...
Paint paint = new Paint();
paint.setShadowLayer(8.f, 0, 0, 0xff000000); // this line makes terribly slow drawing
canvas.drawRect(left, top, right, bottom, paint);

How can I make this faster?

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九公里浅绿 2025-01-01 06:46:34

在四处寻找加快大文本阴影速度的方法时，我偶然发现了这个问题和答案：

setShadowLayer Android API 差异

通过使用：

myView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

我极大地加快了应用程序中所有文本阴影的速度。

以下是我如何使用它的示例：

/**
 * Set a backlight (shadow) on the passed TextView.
 * @param textView
 */
void setBacklight(TextView textView) {
    if (textView != null) {
        float textSize = textView.getTextSize();

        textView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

        textView.setShadowLayer(textSize,0,0,getColor(R.color.color_backlight));
    }
}

根据此文档：

https ://developer.android.com/guide/topics/graphics/hardware-accel.html

它表示您可以禁用视图的硬件加速。

我不知道为什么，但不知怎的，这神奇地加速了我的 TextView 阴影层。

我知道，我知道。 Canvas 或 Paint 类不存在该方法。因此，要回答具体问题（这样我就不会被每个人批评......），您可以将其设置在您打算绘制画布的视图上。像这样：

void inTheShadows(View view) {
    float left = 0f;
    float top = 0f;
    float right = 10f;
    float bottom = 10f;
    Canvas canvas = new Canvas();
    Paint paint = new Paint();

    paint.setShadowLayer(8.f, 0, 0, 0xff000000);

    canvas.drawRect(left, top, right, bottom, paint);

    view.setLayerType(View.LAYER_TYPE_SOFTWARE,null);

    view.onDrawForeground(canvas);
}

While digging around to find a way to speed up my large text shadows, I stumbled on this question and answer:

setShadowLayer Android API differences

By using:

myView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

I drastically sped up all the text shadows in my app.

Here is a sample of how I use it:

/**
 * Set a backlight (shadow) on the passed TextView.
 * @param textView
 */
void setBacklight(TextView textView) {
    if (textView != null) {
        float textSize = textView.getTextSize();

        textView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);

        textView.setShadowLayer(textSize,0,0,getColor(R.color.color_backlight));
    }
}

According to this doc:

https://developer.android.com/guide/topics/graphics/hardware-accel.html

It says that you can disable hardware acceleration for the view.

I don't know why, but somehow this magically speeds up my TextView shadow layers.

I know, I know. That method doesn't exist for the Canvas or Paint classes. So to answer the specific question (so I don't get blasted by everyone...), you could set that on the View that you intend to draw the canvas. Like this:

void inTheShadows(View view) {
    float left = 0f;
    float top = 0f;
    float right = 10f;
    float bottom = 10f;
    Canvas canvas = new Canvas();
    Paint paint = new Paint();

    paint.setShadowLayer(8.f, 0, 0, 0xff000000);

    canvas.drawRect(left, top, right, bottom, paint);

    view.setLayerType(View.LAYER_TYPE_SOFTWARE,null);

    view.onDrawForeground(canvas);
}

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