Bitmap scaling up to 80 percent

Question

I am trying to scale a bitmap using options.inSampleSize , but from what I understand, the display looks like this

• If inSampleSize 1, then the resulting image will be 100%

• If inSampleSize 2, then the resulting image will be 50%

• If inSampleSize 3, then the resulting image is 33%

• If inSampleSize 4, then the resulting image will be 25%

• If inSampleSize 5, then the resulting image will be 20%

But I want to get the resulting image of 80% for scaling. How to get it?

Answer 1

I think you may not understand the point inSampleSize. It is designed to save memory. If you are just trying to draw an image with 80% of its size, you can use the matrix to resize it (or up) after you read the file in memory.

Answer 2

Can't you use the Bitmap.createScaledBitmap method?

 int srcWidth = srcBitmap.getWidth(); int srcHeight = srcBitmap.getHeight(); int dstWidth = (int)(srcWidth*0.8f); int dstHeight = (int)(srcHeight*0.8f); Bitmap dstBitmap = Bitmap.createScaledBitmap(srcBitmap, dstWidth, dstHeight, true); 

Answer 3

You can use the calculateSampleSize function from this class. This is purely calculated.

 package com.abhan.example.util; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.BitmapFactory.Options; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; public class ScalingUtilities { public static Bitmap decodeResource(Resources res, int resId, int dstWidth, int dstHeight, ScalingLogic scalingLogic) { Options options = new Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeResource(res, resId, options); options.inJustDecodeBounds = false; options.inSampleSize = calculateSampleSize(options.outWidth, options.outHeight, dstWidth, dstHeight, scalingLogic); Bitmap unscaledBitmap = BitmapFactory.decodeResource(res, resId, options); return unscaledBitmap; } public static Bitmap createScaledBitmap(Bitmap unscaledBitmap, int dstWidth, int dstHeight, ScalingLogic scalingLogic) { Rect srcRect = calculateSrcRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(), dstWidth, dstHeight, scalingLogic); Rect dstRect = calculateDstRect(unscaledBitmap.getWidth(), unscaledBitmap.getHeight(), dstWidth, dstHeight, scalingLogic); Bitmap scaledBitmap = Bitmap.createBitmap(dstRect.width(), dstRect.height(), Config.ARGB_8888); Canvas canvas = new Canvas(scaledBitmap); canvas.drawBitmap(unscaledBitmap, srcRect, dstRect, new Paint( Paint.FILTER_BITMAP_FLAG)); return scaledBitmap; } public static enum ScalingLogic { CROP, FIT } public static int calculateSampleSize(int srcWidth, int srcHeight, int dstWidth, int dstHeight, ScalingLogic scalingLogic) { if (scalingLogic == ScalingLogic.FIT) { final float srcAspect = (float) srcWidth / (float) srcHeight; final float dstAspect = (float) dstWidth / (float) dstHeight; if (srcAspect > dstAspect) { return srcWidth / dstWidth; } else { return srcHeight / dstHeight; } } else { final float srcAspect = (float) srcWidth / (float) srcHeight; final float dstAspect = (float) dstWidth / (float) dstHeight; if (srcAspect > dstAspect) { return srcHeight / dstHeight; } else { return srcWidth / dstWidth; } } } public static Rect calculateSrcRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight, ScalingLogic scalingLogic) { if (scalingLogic == ScalingLogic.CROP) { final float srcAspect = (float) srcWidth / (float) srcHeight; final float dstAspect = (float) dstWidth / (float) dstHeight; if (srcAspect > dstAspect) { final int srcRectWidth = (int) (srcHeight * dstAspect); final int srcRectLeft = (srcWidth - srcRectWidth) / 2; return new Rect(srcRectLeft, 0, srcRectLeft + srcRectWidth, srcHeight); } else { final int srcRectHeight = (int) (srcWidth / dstAspect); final int scrRectTop = (int) (srcHeight - srcRectHeight) / 2; return new Rect(0, scrRectTop, srcWidth, scrRectTop + srcRectHeight); } } else { return new Rect(0, 0, srcWidth, srcHeight); } } public static Rect calculateDstRect(int srcWidth, int srcHeight, int dstWidth, int dstHeight, ScalingLogic scalingLogic) { if (scalingLogic == ScalingLogic.FIT) { final float srcAspect = (float) srcWidth / (float) srcHeight; final float dstAspect = (float) dstWidth / (float) dstHeight; if (srcAspect > dstAspect) { return new Rect(0, 0, dstWidth, (int) (dstWidth / srcAspect)); } else { return new Rect(0, 0, (int) (dstHeight * srcAspect), dstHeight); } } else { return new Rect(0, 0, dstWidth, dstHeight); } } } 

Hope this helps you.

Thanks.