摘要：進(jìn)行縮放然后比對(duì)進(jìn)行縮放調(diào)用中轉(zhuǎn)換成創(chuàng)建操作圖片用的對(duì)象計(jì)算縮放比例設(shè)置縮放比例建立新的，其內(nèi)容是對(duì)原的縮放后的圖至此，本篇已結(jié)束，如有不對(duì)的地方，歡迎您的建議與指正。同時(shí)期待您的關(guān)注，感謝您的閱讀，謝謝

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Drawable 使用方法詳解請(qǐng)看上篇文章.
Drawable 使用方法詳解

本篇文章主要介紹 Android 開(kāi)發(fā)中的部分知識(shí)點(diǎn)，通過(guò)閱讀本篇文章，您將收獲以下內(nèi)容:

從資源中獲取Bitmap
Bitmap ----> byte[]
byte[] ----> Bitmap
Bitmap 縮放方法
Drawable ----> Bitmap
圓角圖片
獲取帶倒影的圖片
bitmap ----> Drawable
drawable縮放 ，先轉(zhuǎn) bitmap 后縮放

    // 1.從資源中獲取Bitmap
    public void UseBitmap(Context context, ImageView imageView, int drawableId) {

        Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(),
                drawableId);
        imageView.setImageBitmap(bitmap);

    }

    // 2.Bitmap ---> byte[]
    public byte[] BitmapToBytes(Bitmap bitmap) {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
        return baos.toByteArray();
    }

    // 3.byte[] ---->bitmap
    public Bitmap BytesToBitmap(byte[] b) {
        if (b.length != 0) {
            return BitmapFactory.decodeByteArray(b, 0, b.length);
        } else {
            return null;
        }
    }

    // 4.Bitmap 縮放方法
    public static Bitmap ZoomBitmap(Bitmap bitmap, int width, int heigh) {
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scalewidth = (float) width / w;
        float scaleheigh = (float) heigh / h;
        matrix.postScale(scalewidth, scaleheigh);
        Bitmap newBmp = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix, true);
        return newBmp;

    }

    // 5. Drawable----> Bitmap
    public static Bitmap DrawableToBitmap(Drawable drawable) {

        // 獲取 drawable 長(zhǎng)寬
        int width = drawable.getIntrinsicWidth();
        int heigh = drawable.getIntrinsicHeight();

        drawable.setBounds(0, 0, width, heigh);

        // 獲取drawable的顏色格式
        Bitmap.Config config = drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                : Bitmap.Config.RGB_565;
        // 創(chuàng)建bitmap
        Bitmap bitmap = Bitmap.createBitmap(width, heigh, config);
        // 創(chuàng)建bitmap畫布
        Canvas canvas = new Canvas(bitmap);
        // 將drawable 內(nèi)容畫到畫布中
        drawable.draw(canvas);
        return bitmap;
    }

-實(shí)現(xiàn)效果如下：

實(shí)現(xiàn)代碼如下：

    // 6.圓角圖片
    public static Bitmap SetRoundCornerBitmap(Bitmap bitmap, float roundPx) {
        int width = bitmap.getWidth();
        int heigh = bitmap.getHeight();
        // 創(chuàng)建輸出bitmap對(duì)象
        Bitmap outmap = Bitmap.createBitmap(width, heigh,
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(outmap);
        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, width, heigh);
        final RectF rectf = new RectF(rect);
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectf, roundPx, roundPx, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return outmap;
    }

實(shí)現(xiàn)效果如下：

實(shí)現(xiàn)代碼如下：

    // 7.獲取帶倒影的圖片
    public static Bitmap CreateReflectionImageWithOrigin(Bitmap bitmap) {

        final int reflectionGap = 4;
        int w = bitmap.getWidth();
        int h = bitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);

        Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, h / 2, w,
                h / 2, matrix, false);

        Bitmap bitmapWithReflection = Bitmap.createBitmap(w, (h + h / 2),
                Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmapWithReflection);
        canvas.drawBitmap(bitmap, 0, 0, null);
        Paint deafalutPaint = new Paint();
        canvas.drawRect(0, h, w, h + reflectionGap, deafalutPaint);

        canvas.drawBitmap(reflectionImage, 0, h + reflectionGap, null);

        Paint paint = new Paint();
        LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
                bitmapWithReflection.getHeight() + reflectionGap, 0x70ffffff,
                0x00ffffff, Shader.TileMode.CLAMP);
        paint.setShader(shader);
        // Set the Transfer mode to be porter duff and destination in
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
        // Draw a rectangle using the paint with our linear gradient
        canvas.drawRect(0, h, w, bitmapWithReflection.getHeight()
                + reflectionGap, paint);
        return bitmapWithReflection;
    }

    // 8. bitmap ---Drawable
    public static Drawable BitmapToDrawable(Bitmap bitmap, Context context) {
        BitmapDrawable drawbale = new BitmapDrawable(context.getResources(),
                bitmap);
        return drawbale;
    }

drawable縮放 ，先轉(zhuǎn) bitmap，調(diào)用 5中的方法 后縮放。

    // 9. drawable進(jìn)行縮放 ---> bitmap 然后比對(duì)bitmap進(jìn)行縮放
    public static Drawable ZoomDrawable(Drawable drawable, int w, int h) {
        int width = drawable.getIntrinsicWidth();
        int height = drawable.getIntrinsicHeight();
        // 調(diào)用5 中 drawable轉(zhuǎn)換成bitmap
        Bitmap oldbmp = DrawableToBitmap(drawable);

        // 創(chuàng)建操作圖片用的Matrix對(duì)象
        Matrix matrix = new Matrix();
        // 計(jì)算縮放比例
        float sx = ((float) w / width);
        float sy = ((float) h / height);
        // 設(shè)置縮放比例
        matrix.postScale(sx, sy);
        // 建立新的bitmap，其內(nèi)容是對(duì)原bitmap的縮放后的圖
        Bitmap newbmp = Bitmap.createBitmap(oldbmp, 0, 0, width, height,
                matrix, true);
        return new BitmapDrawable(newbmp);
    }

至此，本篇已結(jié)束，如有不對(duì)的地方，歡迎您的建議與指正。同時(shí)期待您的關(guān)注，感謝您的閱讀，謝謝！