android 文本高斯模糊

实现 Android 文本高斯模糊可以使用 RenderScript 或 Bitmap API。

使用 RenderScript 进行文本高斯模糊：

1. 创建 RenderScript 对象

RenderScript rs = RenderScript.create(context);

2. 创建用于高斯模糊的脚本

ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));

3. 将文本转换为 Bitmap 对象

TextPaint textPaint = new TextPaint();
textPaint.setColor(Color.WHITE);
textPaint.setTextSize(50);
StaticLayout staticLayout = new StaticLayout(text, textPaint, width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
Bitmap bitmap = Bitmap.createBitmap(staticLayout.getWidth(), staticLayout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
staticLayout.draw(canvas);

4. 将 Bitmap 转换为 Allocation 对象

Allocation input = Allocation.createFromBitmap(rs, bitmap);
Allocation output = Allocation.createTyped(rs, input.getType());

5. 设置高斯模糊半径并执行高斯模糊

script.setRadius(radius);
script.setInput(input);
script.forEach(output);

6. 将高斯模糊后的结果绘制到 Canvas 上

output.copyTo(bitmap);
canvas.drawBitmap(bitmap, 0, 0, null);

完整代码：

RenderScript rs = RenderScript.create(context);
ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
TextPaint textPaint = new TextPaint();
textPaint.setColor(Color.WHITE);
textPaint.setTextSize(50);
StaticLayout staticLayout = new StaticLayout(text, textPaint, width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
Bitmap bitmap = Bitmap.createBitmap(staticLayout.getWidth(), staticLayout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
staticLayout.draw(canvas);
Allocation input = Allocation.createFromBitmap(rs, bitmap);
Allocation output = Allocation.createTyped(rs, input.getType());
script.setRadius(radius);
script.setInput(input);
script.forEach(output);
output.copyTo(bitmap);
canvas.drawBitmap(bitmap, 0, 0, null);

使用 Bitmap API 进行文本高斯模糊：

1. 将文本绘制到 Bitmap 上

TextPaint textPaint = new TextPaint();
textPaint.setColor(Color.WHITE);
textPaint.setTextSize(50);
StaticLayout staticLayout = new StaticLayout(text, textPaint, width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
Bitmap bitmap = Bitmap.createBitmap(staticLayout.getWidth(), staticLayout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
staticLayout.draw(canvas);

2. 调用 Bitmap 的 blur 方法进行高斯模糊

bitmap = bitmap.copy(bitmap.getConfig(), true);
Bitmap blurredBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
RenderScript rs = RenderScript.create(context);
Allocation input = Allocation.createFromBitmap(rs, bitmap);
Allocation output = Allocation.createFromBitmap(rs, blurredBitmap);
ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
script.setRadius(radius);
script.setInput(input);
script.forEach(output);
output.copyTo(blurredBitmap);

3. 将高斯模糊后的结果绘制到 Canvas 上

canvas.drawBitmap(blurredBitmap, 0, 0, null);

完整代码：

TextPaint textPaint = new TextPaint();
textPaint.setColor(Color.WHITE);
textPaint.setTextSize(50);
StaticLayout staticLayout = new StaticLayout(text, textPaint, width, Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
Bitmap bitmap = Bitmap.createBitmap(staticLayout.getWidth(), staticLayout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
staticLayout.draw(canvas);
bitmap = bitmap.copy(bitmap.getConfig(), true);
Bitmap blurredBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
RenderScript rs = RenderScript.create(context);
Allocation input = Allocation.createFromBitmap(rs, bitmap);
Allocation output = Allocation.createFromBitmap(rs, blurredBitmap);
ScriptIntrinsicBlur script = ScriptIntrinsicBlur.create(rs, Element.U8_4(rs));
script.setRadius(radius);
script.setInput(input);
script.forEach(output);
output.copyTo(blurredBitmap);
canvas.drawBitmap(blurredBitmap, 0, 0, null);