android - 安卓纹理文本

Question

如何制作带有纹理而不是文本颜色或渐变的文本（例如 png 文件）？像这样的东西。我理解逻辑，我应该使文本颜色透明并放在文本位图下。我想我无法用Textview. 而且我不知道如何使用画布或 OpenGL 来做到这一点。请问有什么想法吗？

Answer 1

这是一种使用PorterDuffXfermode.

public class MainActivity extends Activity {
    private EditText mEditText;
    private ImageView mImageView;
    private Bitmap mTexture;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mEditText = (EditText) findViewById(R.id.activity_main_edittext);
        mImageView = (ImageView) findViewById(R.id.activity_main_image);

        mTexture = BitmapFactory.decodeResource(getResources(),
                R.drawable.texture);
    }

    public void onTextCreate(View v) {
        final String text = mEditText.getEditableText().toString();

        Bitmap result = Bitmap.createBitmap(mTexture.getWidth(),
                mTexture.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(result);
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setTextSize(200);
        paint.setARGB(255, 0, 0, 0);

        canvas.drawText(text, 200, 200, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(mTexture, 0, 0, paint);
        paint.setXfermode(null);

        mImageView.setImageBitmap(result);
    }
}

布局非常简单：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <EditText
        android:id="@+id/activity_main_edittext"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:hint="Write a sample text" />

    <ImageView
        android:id="@+id/activity_main_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true" />

    <Button
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:onClick="onTextCreate"
        android:text="Do it!" />

</RelativeLayout>

此代码使用canvas.drawText(). 如果你想使用一个常规的TextView，你可以：

• 创建TextView
• 设置文本
• 使用TextView_textView.draw(canvas);
• 而不是canvas.drawText()使用canvas.drawBitmap()

Answer 2

这是来自http://teamyoda.wordpress.com/2012/07/23/drawing-text-in-opengl-for-android/的片段- JVitela 的回答

 // Create an empty, mutable bitmap
Bitmap bitmap = Bitmap.createBitmap(256, 256, Bitmap.Config.ARGB_4444);

// get a canvas to paint over the bitmap
Canvas canvas = new Canvas(bitmap);
bitmap.eraseColor(0);

// get a background image from resources
// note the image format must match the bitmap format
Drawable background = context.getResources().getDrawable(R.drawable.background);
background.setBounds(0, 0, 256, 256);
background.draw(canvas); // draw the background to our bitmap

// Draw the text
Paint textPaint = new Paint();
textPaint.setTextSize(32);
textPaint.setAntiAlias(true);
textPaint.setARGB(0xff, 0×00, 0×00, 0×00);

// draw the text centered
canvas.drawText(“Hello World”, 16,112, textPaint);

//Generate one texture pointer…
gl.glGenTextures(1, textures, 0);

//…and bind it to our array
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);

//Create Nearest Filtered Texture
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);

//Different possible texture parameters, e.g. GL10.GL_CLAMP_TO_EDGE
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT);

//Use the Android GLUtils to specify a two-dimensional texture image from our bitmap
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);

//Clean up
bitmap.recycle();

Answer 3

很抱歉发布这么晚，但我想我会有所帮助。因此，要制作带纹理的文本，例如，您的layout/文件夹中有一个名为my_layout.xml的 文件，其定义如下：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">

    <TextView
    android:id="@+id/some_text_id"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:text="@string/some_text"/>

</RelativeLayout>

在您的drawable/ 文件夹中，您有一张名为texture.png的图片，您只需在 java 代码中引用（例如在 MainActivity 类中）这样：

public class MainActivity extends Activity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_layout);
        TextView welcome = (TextView) findViewById(R.id.some_text_id);
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.texture);
        Shader shader = new BitmapShader(bitmap,Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
        welcome.getPaint().setShader(shader);

    }
}