如何在不创建新位图的情况下拥有圆形、中心裁剪的 imageView?
How to have a circular, center-cropped imageView, without creating a new bitmap?
注意:我知道有很多关于此的问题和存储库,但 none 似乎符合我尝试实现的目标。
背景
给定任意纵横比的位图,我希望将其设置为 ImageView 的内容(仅使用可绘制对象,不扩展 ImageView),这样内容将被居中裁剪,但在圆的形状。
所有这一切,使用最少的内存,因为有时图像可能非常大。我不想为此创建一个全新的位图。内容已经存在...
问题
我发现的所有解决方案都缺少我写过的东西之一:有些不居中裁剪,有些假设图像是方形的,有些从给定的位图创建一个新的位图...
我试过的
除了尝试各种存储库外,我还尝试了 this tutorial,并尝试针对非正方形纵横比的情况修复它,但我失败了。
这是它的代码,以防网站关闭:
public class RoundImage extends Drawable {
private final Bitmap mBitmap;
private final Paint mPaint;
private final RectF mRectF;
private final int mBitmapWidth;
private final int mBitmapHeight;
public RoundImage(Bitmap bitmap) {
mBitmap = bitmap;
mRectF = new RectF();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
final BitmapShader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mPaint.setShader(shader);
mBitmapWidth = mBitmap.getWidth();
mBitmapHeight = mBitmap.getHeight();
}
@Override
public void draw(Canvas canvas) {
canvas.drawOval(mRectF, mPaint);
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
mRectF.set(bounds);
}
@Override
public void setAlpha(int alpha) {
if (mPaint.getAlpha() != alpha) {
mPaint.setAlpha(alpha);
invalidateSelf();
}
}
@Override
public void setColorFilter(ColorFilter cf) {
mPaint.setColorFilter(cf);
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
@Override
public int getIntrinsicWidth() {
return mBitmapWidth;
}
@Override
public int getIntrinsicHeight() {
return mBitmapHeight;
}
public void setAntiAlias(boolean aa) {
mPaint.setAntiAlias(aa);
invalidateSelf();
}
@Override
public void setFilterBitmap(boolean filter) {
mPaint.setFilterBitmap(filter);
invalidateSelf();
}
@Override
public void setDither(boolean dither) {
mPaint.setDither(dither);
invalidateSelf();
}
public Bitmap getBitmap() {
return mBitmap;
}
}
我找到了一个非常好的解决方案 (here) 完全可以满足我的需要,除了它在 ImageView 本身中使用它,而不是创建可绘制对象。这意味着我无法将其设置为视图的背景等。
问题
我怎样才能做到这一点?
编辑:这是当前代码,因为我想添加边框,它也有这样的代码:
public class SimpleRoundedDrawable extends BitmapDrawable {
private final Path p = new Path();
private final Paint mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
public SimpleRoundedDrawable(final Resources res, final Bitmap bitmap) {
super(res, bitmap);
mBorderPaint.setStyle(Paint.Style.STROKE);
}
public SimpleRoundedDrawable setBorder(float borderWidth, @ColorInt int borderColor) {
mBorderPaint.setStrokeWidth(borderWidth);
mBorderPaint.setColor(borderColor);
invalidateSelf();
return this;
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
p.rewind();
p.addCircle(bounds.width() / 2,
bounds.height() / 2,
Math.min(bounds.width(), bounds.height()) / 2,
Path.Direction.CW);
}
@Override
public void draw(Canvas canvas) {
canvas.clipPath(p);
super.draw(canvas);
final float width = getBounds().width(), height = getBounds().height();
canvas.drawCircle(width / 2, height / 2, Math.min(width, height) / 2, mBorderPaint);
}
}
我希望事情真的应该是这样的。
编辑:似乎该解决方案仅适用于特定的 Android 版本,因为它不适用于 Android 4.2.2。相反,它显示方形图像。
编辑:上面的解决方案似乎也比使用 BitmapShader (Link here) 效率低得多。知道如何在可绘制对象中而不是在自定义的 ImageView 中使用它真的很棒
--
这是以下解决方案的当前修改版本。希望对某些人有用:
public class SimpleRoundedDrawable extends Drawable {
final Paint mMaskPaint = new Paint(Paint.ANTI_ALIAS_FLAG), mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
Bitmap mBitmap;
int mSide;
float mRadius;
public SimpleRoundedDrawable() {
this(null);
}
public SimpleRoundedDrawable(Bitmap bitmap) {
this(bitmap, 0, 0);
}
public SimpleRoundedDrawable(Bitmap bitmap, float width, @ColorInt int color) {
mBorderPaint.setStyle(Paint.Style.STROKE);
mBitmap = bitmap;
mSide = mBitmap == null ? 0 : Math.min(bitmap.getWidth(), bitmap.getHeight());
mBorderPaint.setStrokeWidth(width);
mBorderPaint.setColor(color);
}
public SimpleRoundedDrawable setBitmap(final Bitmap bitmap) {
mBitmap = bitmap;
mSide = Math.min(bitmap.getWidth(), bitmap.getHeight());
invalidateSelf();
return this;
}
public SimpleRoundedDrawable setBorder(float width, @ColorInt int color) {
mBorderPaint.setStrokeWidth(width);
mBorderPaint.setColor(color);
invalidateSelf();
return this;
}
@Override
protected void onBoundsChange(Rect bounds) {
if (mBitmap == null)
return;
Matrix matrix = new Matrix();
RectF src = new RectF(0, 0, mSide, mSide);
src.offset((mBitmap.getWidth() - mSide) / 2f, (mBitmap.getHeight() - mSide) / 2f);
RectF dst = new RectF(bounds);
final float strokeWidth = mBorderPaint.getStrokeWidth();
if (strokeWidth > 0)
dst.inset(strokeWidth, strokeWidth);
matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
Shader shader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
shader.setLocalMatrix(matrix);
mMaskPaint.setShader(shader);
matrix.mapRect(src);
mRadius = src.width() / 2f;
}
@Override
public void draw(Canvas canvas) {
Rect b = getBounds();
if (mBitmap != null)
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), mRadius, mMaskPaint);
final float strokeWidth = mBorderPaint.getStrokeWidth();
if (strokeWidth > 0)
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), mRadius + strokeWidth / 2, mBorderPaint);
}
@Override
public void setAlpha(int alpha) {
mMaskPaint.setAlpha(alpha);
invalidateSelf();
}
@Override
public void setColorFilter(ColorFilter cf) {
mMaskPaint.setColorFilter(cf);
invalidateSelf();
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
}
如果我没听错的话,你的 Drawable
class 会是这样的:
public class CroppedDrawable extends BitmapDrawable {
private Path p = new Path();
public CroppedDrawable(Bitmap b) {
super(b);
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
p.rewind();
p.addCircle(bounds.width() / 2,
bounds.height() / 2,
Math.min(bounds.width(), bounds.height()) / 2,
Path.Direction.CW);
}
@Override
public void draw(Canvas canvas) {
canvas.clipPath(p);
super.draw(canvas);
}
}
示例用法为:
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.mila);
CroppedDrawable cd = new CroppedDrawable(bitmap);
imageView.setImageDrawable(cd);
使用您之前的示例图片,会给出如下内容:
看起来,使用 "clipPath" 效率不高,需要在 4.3 及以下版本上禁用硬件加速。
更好的解决方案是在这个库中使用类似的东西,使用 BitmapShader:
https://github.com/hdodenhof/CircleImageView
基于:
http://www.curious-creature.com/2012/12/11/android-recipe-1-image-with-rounded-corners/
相关代码为:
BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
RectF rect = new RectF(0.0f, 0.0f, width, height);
// rect contains the bounds of the shape
// radius is the radius in pixels of the rounded corners
// paint contains the shader that will texture the shape
canvas.drawRoundRect(rect, radius, radius, paint);
如果输入是位图,我仍然希望知道如何在可绘制对象中完成所有操作。
试试这个极简风俗 Drawable
并修改它以满足您的需要:
class D extends Drawable {
Bitmap bitmap;
Paint maskPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
Paint borderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
int side;
float radius;
public D(Bitmap wrappedBitmap) {
bitmap = wrappedBitmap;
borderPaint.setStyle(Paint.Style.STROKE);
borderPaint.setStrokeWidth(16);
borderPaint.setColor(0xcc220088);
side = Math.min(bitmap.getWidth(), bitmap.getHeight());
}
@Override
protected void onBoundsChange(Rect bounds) {
Matrix matrix = new Matrix();
RectF src = new RectF(0, 0, side, side);
src.offset((bitmap.getWidth() - side) / 2f, (bitmap.getHeight() - side) / 2f);
RectF dst = new RectF(bounds);
dst.inset(borderPaint.getStrokeWidth(), borderPaint.getStrokeWidth());
matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
Shader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
shader.setLocalMatrix(matrix);
maskPaint.setShader(shader);
matrix.mapRect(src);
radius = src.width() / 2f;
}
@Override
public void draw(Canvas canvas) {
Rect b = getBounds();
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), radius, maskPaint);
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), radius + borderPaint.getStrokeWidth() / 2, borderPaint);
}
@Override public void setAlpha(int alpha) {}
@Override public void setColorFilter(ColorFilter cf) {}
@Override public int getOpacity() {return PixelFormat.TRANSLUCENT;}
}
基于我的 CircleImageView 库的 CircleImageDrawable 快速草稿。这不会创建新的位图,而是使用位图着色器来实现所需的效果并居中裁剪图像。
public class CircleImageDrawable extends Drawable {
private final RectF mBounds = new RectF();
private final RectF mDrawableRect = new RectF();
private final RectF mBorderRect = new RectF();
private final Matrix mShaderMatrix = new Matrix();
private final Paint mBitmapPaint = new Paint();
private final Paint mBorderPaint = new Paint();
private int mBorderColor = Color.BLACK;
private int mBorderWidth = 0;
private Bitmap mBitmap;
private BitmapShader mBitmapShader;
private int mBitmapWidth;
private int mBitmapHeight;
private float mDrawableRadius;
private float mBorderRadius;
public CircleImageDrawable(Bitmap bitmap) {
mBitmap = bitmap;
mBitmapHeight = mBitmap.getHeight();
mBitmapWidth = mBitmap.getWidth();
}
@Override
public void draw(Canvas canvas) {
canvas.drawCircle(mBounds.width() / 2.0f, mBounds.height() / 2.0f, mDrawableRadius, mBitmapPaint);
if (mBorderWidth != 0) {
canvas.drawCircle(mBounds.width() / 2.0f, mBounds.height() / 2.0f, mBorderRadius, mBorderPaint);
}
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
mBounds.set(bounds);
setup();
}
private void setup() {
mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mBitmapPaint.setAntiAlias(true);
mBitmapPaint.setShader(mBitmapShader);
mBorderPaint.setStyle(Paint.Style.STROKE);
mBorderPaint.setAntiAlias(true);
mBorderPaint.setColor(mBorderColor);
mBorderPaint.setStrokeWidth(mBorderWidth);
mBorderRect.set(mBounds);
mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2.0f, (mBorderRect.width() - mBorderWidth) / 2.0f);
mDrawableRect.set(mBorderRect);
mDrawableRect.inset(mBorderWidth, mBorderWidth);
mDrawableRadius = Math.min(mDrawableRect.height() / 2.0f, mDrawableRect.width() / 2.0f);
updateShaderMatrix();
invalidateSelf();
}
private void updateShaderMatrix() {
float scale;
float dx = 0;
float dy = 0;
mShaderMatrix.set(null);
if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
scale = mDrawableRect.height() / (float) mBitmapHeight;
dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
} else {
scale = mDrawableRect.width() / (float) mBitmapWidth;
dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
}
mShaderMatrix.setScale(scale, scale);
mShaderMatrix.postTranslate((int) (dx + 0.5f) + mDrawableRect.left, (int) (dy + 0.5f) + mDrawableRect.top);
mBitmapShader.setLocalMatrix(mShaderMatrix);
}
@Override
public void setAlpha(int alpha) {
mBitmapPaint.setAlpha(alpha);
invalidateSelf();
}
@Override
public void setColorFilter(ColorFilter colorFilter) {
mBitmapPaint.setColorFilter(colorFilter);
invalidateSelf();
}
@Override
public int getOpacity() {
return 0;
}
}
已经有一个内置的方法来完成这个,它是 1 行代码 (ThumbnailUtils.extractThumbnail())
int dimension = getSquareCropDimensionForBitmap(bitmap);
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension);
...
//I added this method because people keep asking how
//to calculate the dimensions of the bitmap...see comments below
public int getSquareCropDimensionForBitmap(Bitmap bitmap)
{
//If the bitmap is wider than it is tall
//use the height as the square crop dimension
if (bitmap.getWidth() >= bitmap.getHeight())
{
dimension = bitmap.getHeight();
}
//If the bitmap is taller than it is wide
//use the width as the square crop dimension
else
{
dimension = bitmap.getWidth();
}
}
如果你想回收位图对象,你可以通过选项来实现:
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
下面是文档的 link:
ThumbnailUtils Documentation
注意:我知道有很多关于此的问题和存储库,但 none 似乎符合我尝试实现的目标。
背景
给定任意纵横比的位图,我希望将其设置为 ImageView 的内容(仅使用可绘制对象,不扩展 ImageView),这样内容将被居中裁剪,但在圆的形状。
所有这一切,使用最少的内存,因为有时图像可能非常大。我不想为此创建一个全新的位图。内容已经存在...
问题
我发现的所有解决方案都缺少我写过的东西之一:有些不居中裁剪,有些假设图像是方形的,有些从给定的位图创建一个新的位图...
我试过的
除了尝试各种存储库外,我还尝试了 this tutorial,并尝试针对非正方形纵横比的情况修复它,但我失败了。
这是它的代码,以防网站关闭:
public class RoundImage extends Drawable {
private final Bitmap mBitmap;
private final Paint mPaint;
private final RectF mRectF;
private final int mBitmapWidth;
private final int mBitmapHeight;
public RoundImage(Bitmap bitmap) {
mBitmap = bitmap;
mRectF = new RectF();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
final BitmapShader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mPaint.setShader(shader);
mBitmapWidth = mBitmap.getWidth();
mBitmapHeight = mBitmap.getHeight();
}
@Override
public void draw(Canvas canvas) {
canvas.drawOval(mRectF, mPaint);
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
mRectF.set(bounds);
}
@Override
public void setAlpha(int alpha) {
if (mPaint.getAlpha() != alpha) {
mPaint.setAlpha(alpha);
invalidateSelf();
}
}
@Override
public void setColorFilter(ColorFilter cf) {
mPaint.setColorFilter(cf);
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
@Override
public int getIntrinsicWidth() {
return mBitmapWidth;
}
@Override
public int getIntrinsicHeight() {
return mBitmapHeight;
}
public void setAntiAlias(boolean aa) {
mPaint.setAntiAlias(aa);
invalidateSelf();
}
@Override
public void setFilterBitmap(boolean filter) {
mPaint.setFilterBitmap(filter);
invalidateSelf();
}
@Override
public void setDither(boolean dither) {
mPaint.setDither(dither);
invalidateSelf();
}
public Bitmap getBitmap() {
return mBitmap;
}
}
我找到了一个非常好的解决方案 (here) 完全可以满足我的需要,除了它在 ImageView 本身中使用它,而不是创建可绘制对象。这意味着我无法将其设置为视图的背景等。
问题
我怎样才能做到这一点?
编辑:这是当前代码,因为我想添加边框,它也有这样的代码:
public class SimpleRoundedDrawable extends BitmapDrawable {
private final Path p = new Path();
private final Paint mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
public SimpleRoundedDrawable(final Resources res, final Bitmap bitmap) {
super(res, bitmap);
mBorderPaint.setStyle(Paint.Style.STROKE);
}
public SimpleRoundedDrawable setBorder(float borderWidth, @ColorInt int borderColor) {
mBorderPaint.setStrokeWidth(borderWidth);
mBorderPaint.setColor(borderColor);
invalidateSelf();
return this;
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
p.rewind();
p.addCircle(bounds.width() / 2,
bounds.height() / 2,
Math.min(bounds.width(), bounds.height()) / 2,
Path.Direction.CW);
}
@Override
public void draw(Canvas canvas) {
canvas.clipPath(p);
super.draw(canvas);
final float width = getBounds().width(), height = getBounds().height();
canvas.drawCircle(width / 2, height / 2, Math.min(width, height) / 2, mBorderPaint);
}
}
我希望事情真的应该是这样的。
编辑:似乎该解决方案仅适用于特定的 Android 版本,因为它不适用于 Android 4.2.2。相反,它显示方形图像。
编辑:上面的解决方案似乎也比使用 BitmapShader (Link here) 效率低得多。知道如何在可绘制对象中而不是在自定义的 ImageView 中使用它真的很棒
-- 这是以下解决方案的当前修改版本。希望对某些人有用:
public class SimpleRoundedDrawable extends Drawable {
final Paint mMaskPaint = new Paint(Paint.ANTI_ALIAS_FLAG), mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
Bitmap mBitmap;
int mSide;
float mRadius;
public SimpleRoundedDrawable() {
this(null);
}
public SimpleRoundedDrawable(Bitmap bitmap) {
this(bitmap, 0, 0);
}
public SimpleRoundedDrawable(Bitmap bitmap, float width, @ColorInt int color) {
mBorderPaint.setStyle(Paint.Style.STROKE);
mBitmap = bitmap;
mSide = mBitmap == null ? 0 : Math.min(bitmap.getWidth(), bitmap.getHeight());
mBorderPaint.setStrokeWidth(width);
mBorderPaint.setColor(color);
}
public SimpleRoundedDrawable setBitmap(final Bitmap bitmap) {
mBitmap = bitmap;
mSide = Math.min(bitmap.getWidth(), bitmap.getHeight());
invalidateSelf();
return this;
}
public SimpleRoundedDrawable setBorder(float width, @ColorInt int color) {
mBorderPaint.setStrokeWidth(width);
mBorderPaint.setColor(color);
invalidateSelf();
return this;
}
@Override
protected void onBoundsChange(Rect bounds) {
if (mBitmap == null)
return;
Matrix matrix = new Matrix();
RectF src = new RectF(0, 0, mSide, mSide);
src.offset((mBitmap.getWidth() - mSide) / 2f, (mBitmap.getHeight() - mSide) / 2f);
RectF dst = new RectF(bounds);
final float strokeWidth = mBorderPaint.getStrokeWidth();
if (strokeWidth > 0)
dst.inset(strokeWidth, strokeWidth);
matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
Shader shader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
shader.setLocalMatrix(matrix);
mMaskPaint.setShader(shader);
matrix.mapRect(src);
mRadius = src.width() / 2f;
}
@Override
public void draw(Canvas canvas) {
Rect b = getBounds();
if (mBitmap != null)
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), mRadius, mMaskPaint);
final float strokeWidth = mBorderPaint.getStrokeWidth();
if (strokeWidth > 0)
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), mRadius + strokeWidth / 2, mBorderPaint);
}
@Override
public void setAlpha(int alpha) {
mMaskPaint.setAlpha(alpha);
invalidateSelf();
}
@Override
public void setColorFilter(ColorFilter cf) {
mMaskPaint.setColorFilter(cf);
invalidateSelf();
}
@Override
public int getOpacity() {
return PixelFormat.TRANSLUCENT;
}
}
如果我没听错的话,你的 Drawable
class 会是这样的:
public class CroppedDrawable extends BitmapDrawable {
private Path p = new Path();
public CroppedDrawable(Bitmap b) {
super(b);
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
p.rewind();
p.addCircle(bounds.width() / 2,
bounds.height() / 2,
Math.min(bounds.width(), bounds.height()) / 2,
Path.Direction.CW);
}
@Override
public void draw(Canvas canvas) {
canvas.clipPath(p);
super.draw(canvas);
}
}
示例用法为:
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.mila);
CroppedDrawable cd = new CroppedDrawable(bitmap);
imageView.setImageDrawable(cd);
使用您之前的示例图片,会给出如下内容:
看起来,使用 "clipPath" 效率不高,需要在 4.3 及以下版本上禁用硬件加速。
更好的解决方案是在这个库中使用类似的东西,使用 BitmapShader:
https://github.com/hdodenhof/CircleImageView
基于:
http://www.curious-creature.com/2012/12/11/android-recipe-1-image-with-rounded-corners/
相关代码为:
BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
RectF rect = new RectF(0.0f, 0.0f, width, height);
// rect contains the bounds of the shape
// radius is the radius in pixels of the rounded corners
// paint contains the shader that will texture the shape
canvas.drawRoundRect(rect, radius, radius, paint);
如果输入是位图,我仍然希望知道如何在可绘制对象中完成所有操作。
试试这个极简风俗 Drawable
并修改它以满足您的需要:
class D extends Drawable {
Bitmap bitmap;
Paint maskPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
Paint borderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
int side;
float radius;
public D(Bitmap wrappedBitmap) {
bitmap = wrappedBitmap;
borderPaint.setStyle(Paint.Style.STROKE);
borderPaint.setStrokeWidth(16);
borderPaint.setColor(0xcc220088);
side = Math.min(bitmap.getWidth(), bitmap.getHeight());
}
@Override
protected void onBoundsChange(Rect bounds) {
Matrix matrix = new Matrix();
RectF src = new RectF(0, 0, side, side);
src.offset((bitmap.getWidth() - side) / 2f, (bitmap.getHeight() - side) / 2f);
RectF dst = new RectF(bounds);
dst.inset(borderPaint.getStrokeWidth(), borderPaint.getStrokeWidth());
matrix.setRectToRect(src, dst, Matrix.ScaleToFit.CENTER);
Shader shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
shader.setLocalMatrix(matrix);
maskPaint.setShader(shader);
matrix.mapRect(src);
radius = src.width() / 2f;
}
@Override
public void draw(Canvas canvas) {
Rect b = getBounds();
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), radius, maskPaint);
canvas.drawCircle(b.exactCenterX(), b.exactCenterY(), radius + borderPaint.getStrokeWidth() / 2, borderPaint);
}
@Override public void setAlpha(int alpha) {}
@Override public void setColorFilter(ColorFilter cf) {}
@Override public int getOpacity() {return PixelFormat.TRANSLUCENT;}
}
基于我的 CircleImageView 库的 CircleImageDrawable 快速草稿。这不会创建新的位图,而是使用位图着色器来实现所需的效果并居中裁剪图像。
public class CircleImageDrawable extends Drawable {
private final RectF mBounds = new RectF();
private final RectF mDrawableRect = new RectF();
private final RectF mBorderRect = new RectF();
private final Matrix mShaderMatrix = new Matrix();
private final Paint mBitmapPaint = new Paint();
private final Paint mBorderPaint = new Paint();
private int mBorderColor = Color.BLACK;
private int mBorderWidth = 0;
private Bitmap mBitmap;
private BitmapShader mBitmapShader;
private int mBitmapWidth;
private int mBitmapHeight;
private float mDrawableRadius;
private float mBorderRadius;
public CircleImageDrawable(Bitmap bitmap) {
mBitmap = bitmap;
mBitmapHeight = mBitmap.getHeight();
mBitmapWidth = mBitmap.getWidth();
}
@Override
public void draw(Canvas canvas) {
canvas.drawCircle(mBounds.width() / 2.0f, mBounds.height() / 2.0f, mDrawableRadius, mBitmapPaint);
if (mBorderWidth != 0) {
canvas.drawCircle(mBounds.width() / 2.0f, mBounds.height() / 2.0f, mBorderRadius, mBorderPaint);
}
}
@Override
protected void onBoundsChange(Rect bounds) {
super.onBoundsChange(bounds);
mBounds.set(bounds);
setup();
}
private void setup() {
mBitmapShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
mBitmapPaint.setAntiAlias(true);
mBitmapPaint.setShader(mBitmapShader);
mBorderPaint.setStyle(Paint.Style.STROKE);
mBorderPaint.setAntiAlias(true);
mBorderPaint.setColor(mBorderColor);
mBorderPaint.setStrokeWidth(mBorderWidth);
mBorderRect.set(mBounds);
mBorderRadius = Math.min((mBorderRect.height() - mBorderWidth) / 2.0f, (mBorderRect.width() - mBorderWidth) / 2.0f);
mDrawableRect.set(mBorderRect);
mDrawableRect.inset(mBorderWidth, mBorderWidth);
mDrawableRadius = Math.min(mDrawableRect.height() / 2.0f, mDrawableRect.width() / 2.0f);
updateShaderMatrix();
invalidateSelf();
}
private void updateShaderMatrix() {
float scale;
float dx = 0;
float dy = 0;
mShaderMatrix.set(null);
if (mBitmapWidth * mDrawableRect.height() > mDrawableRect.width() * mBitmapHeight) {
scale = mDrawableRect.height() / (float) mBitmapHeight;
dx = (mDrawableRect.width() - mBitmapWidth * scale) * 0.5f;
} else {
scale = mDrawableRect.width() / (float) mBitmapWidth;
dy = (mDrawableRect.height() - mBitmapHeight * scale) * 0.5f;
}
mShaderMatrix.setScale(scale, scale);
mShaderMatrix.postTranslate((int) (dx + 0.5f) + mDrawableRect.left, (int) (dy + 0.5f) + mDrawableRect.top);
mBitmapShader.setLocalMatrix(mShaderMatrix);
}
@Override
public void setAlpha(int alpha) {
mBitmapPaint.setAlpha(alpha);
invalidateSelf();
}
@Override
public void setColorFilter(ColorFilter colorFilter) {
mBitmapPaint.setColorFilter(colorFilter);
invalidateSelf();
}
@Override
public int getOpacity() {
return 0;
}
}
已经有一个内置的方法来完成这个,它是 1 行代码 (ThumbnailUtils.extractThumbnail())
int dimension = getSquareCropDimensionForBitmap(bitmap);
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension);
...
//I added this method because people keep asking how
//to calculate the dimensions of the bitmap...see comments below
public int getSquareCropDimensionForBitmap(Bitmap bitmap)
{
//If the bitmap is wider than it is tall
//use the height as the square crop dimension
if (bitmap.getWidth() >= bitmap.getHeight())
{
dimension = bitmap.getHeight();
}
//If the bitmap is taller than it is wide
//use the width as the square crop dimension
else
{
dimension = bitmap.getWidth();
}
}
如果你想回收位图对象,你可以通过选项来实现:
bitmap = ThumbnailUtils.extractThumbnail(bitmap, dimension, dimension, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
下面是文档的 link: ThumbnailUtils Documentation