I want to scale a bitmap maintaining the aspect ratio, but fitting the required dimensions. This answer scales the bitmap and maintains the aspect ratio, but leaves some blank space unless the image is a perfect square. I need to fill both width and height, just like the FIT_XY ScaleType property of an ImageView.
Based on Streets of Boston's answer, I made this method that scales and returns any Bitmap to a desired width and height, fitting both dimensions (no blank space!). It automatically adapts to more horizontal or more vertical images.
public Bitmap resizeBitmapFitXY(int width, int height, Bitmap bitmap){
Bitmap background = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
float originalWidth = bitmap.getWidth(), originalHeight = bitmap.getHeight();
Canvas canvas = new Canvas(background);
float scale, xTranslation = 0.0f, yTranslation = 0.0f;
if (originalWidth > originalHeight) {
scale = height/originalHeight;
xTranslation = (width - originalWidth * scale)/2.0f;
}
else {
scale = width / originalWidth;
yTranslation = (height - originalHeight * scale)/2.0f;
}
Matrix transformation = new Matrix();
transformation.postTranslate(xTranslation, yTranslation);
transformation.preScale(scale, scale);
Paint paint = new Paint();
paint.setFilterBitmap(true);
canvas.drawBitmap(bitmap, transformation, paint);
return background;
}
This will scale the image to fit into sqaure without any solid color padding in the rest of area and no cropping. If Image is not sqaure then there will be transparent area and aspect ratio of image will as original image.
I have tested it with potrait and lanscape images
import android.graphics.*;
public static Bitmap scalePreserveRatio(Bitmap imageToScale, int destinationWidth,
int destinationHeight) {
if (destinationHeight > 0 && destinationWidth > 0 && imageToScale != null) {
int width = imageToScale.getWidth();
int height = imageToScale.getHeight();
//Calculate the max changing amount and decide which dimension to use
float widthRatio = (float) destinationWidth / (float) width;
float heightRatio = (float) destinationHeight / (float) height;
//Use the ratio that will fit the image into the desired sizes
int finalWidth = (int)Math.floor(width * widthRatio);
int finalHeight = (int)Math.floor(height * widthRatio);
if (finalWidth > destinationWidth || finalHeight > destinationHeight) {
finalWidth = (int)Math.floor(width * heightRatio);
finalHeight = (int)Math.floor(height * heightRatio);
}
//Scale given bitmap to fit into the desired area
imageToScale = Bitmap.createScaledBitmap(imageToScale, finalWidth, finalHeight, true);
//Created a bitmap with desired sizes
Bitmap scaledImage = Bitmap.createBitmap(destinationWidth, destinationHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(scaledImage);
//Draw background color
Paint paint = new Paint();
paint.setColor(Color.TRANSPARENT);
paint.setStyle(Paint.Style.FILL);
canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), paint);
//Calculate the ratios and decide which part will have empty areas (width or height)
float ratioBitmap = (float)finalWidth / (float)finalHeight;
float destinationRatio = (float) destinationWidth / (float) destinationHeight;
float left = ratioBitmap >= destinationRatio ? 0 : (float)(destinationWidth - finalWidth) / 2;
float top = ratioBitmap < destinationRatio ? 0: (float)(destinationHeight - finalHeight) / 2;
canvas.drawBitmap(imageToScale, left, top, null);
return scaledImage;
} else {
return imageToScale;
}
}
from https://stackoverflow.com/a/32810187/9308731
Related
I've been searching for a solution to this problem for quite some time and haven't found anything to match my needs yet.
I want to scale a bitmap to a specific size while maintaining aspect ratio.
Think of it as scaling a bitmap using fitCenter in an ImageView, only in a new bitmap.
The source bitmap has to fit inside the destination bitmap which has a specific size, and the rest of the pixels have to be transparent.
I have tried using Glide like so:
Glide.with(context).load(url)
.asBitmap()
.override(1280, 720)
.fitCenter()
.into(1280, 720)
.get();
But this method returns a bitmap that fits only width (or hight) and wraps the size.
I've heard that using Canvas is a possible solution but haven't found any way of achieving my goal using it.
Any help or insight would be greatly appreciated. I will post any needed clarifications if requested.
I managed to solve it using this function:
Bitmap resizeBitmap(Bitmap image, int destWidth, int destHeight) {
Bitmap background = Bitmap.createBitmap(destWidth, destHeight, Bitmap.Config.ARGB_8888);
float originalWidth = image.getWidth();
float originalHeight = image.getHeight();
Canvas canvas = new Canvas(background);
float scaleX = (float) 1280 / originalWidth;
float scaleY = (float) 720 / originalHeight;
float xTranslation = 0.0f;
float yTranslation = 0.0f;
float scale = 1;
if (scaleX < scaleY) { // Scale on X, translate on Y
scale = scaleX;
yTranslation = (destHeight - originalHeight * scale) / 2.0f;
} else { // Scale on Y, translate on X
scale = scaleY;
xTranslation = (destWidth - originalWidth * scale) / 2.0f;
}
Matrix transformation = new Matrix();
transformation.postTranslate(xTranslation, yTranslation);
transformation.preScale(scale, scale);
Paint paint = new Paint();
paint.setFilterBitmap(true);
canvas.drawBitmap(image, transformation, paint);
return background;
}
I have a bitmap image that is larger than then screen size. I want to scale the image in pixels down to the screen size ? How can i do this ? I want to scale it maintaining aspect ratio not just resize it ?
Kind Regards
Get the screen size and pass those parameters into the following function :
Bitmap.createScaledBitmap(originalimage, width, height, true);
use this function with argument as screenWidth and screenHeight
public Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth) {
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
// Compute the scaling factors to fit the new height and width, respectively.
// To cover the final image, the final scaling will be the bigger
// of these two.
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.max(xScale, yScale);
// Now get the size of the source bitmap when scaled
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
// Let's find out the upper left coordinates if the scaled bitmap
// should be centered in the new size give by the parameters
float left = (newWidth - scaledWidth) / 2;
float top = (newHeight - scaledHeight) / 2;
// The target rectangle for the new, scaled version of the source bitmap will now
// be
RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
// Finally, we create a new bitmap of the specified size and draw our new,
// scaled bitmap onto it.
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawBitmap(source, null, targetRect, null);
return dest;
}
for how to get screen width and height see this
I am new in bitmap.I know how can i resize or scale bitmap in android.But problem is suppose my image is 100x500 or any height & width.Now i want to resize it in square like 100x100.How it is possible
Kindly help me.
For this simple case, the most reasonable thing would be to translate your source image down to the middle, and draw your Bitmap again on a new Canvas. This type of resize is called a center crop in Android. The idea of a center crop is to result in the largest image that fills the entire bounds, and does not change the aspect ratio.
You can implement this yourself, along with other types of resizing and scaling. Basically, you use a Matrix to post your changes, like scaling and moving (translating), and then draw your original Bitmap on a Canvas that takes the Matrix into account.
Here's a method I adopted from another answer here (can't find the original post to properly give credit):
public static Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth)
{
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.max(xScale, yScale);
//get the resulting size after scaling
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
//figure out where we should translate to
float dx = (newWidth - scaledWidth) / 2;
float dy = (newHeight - scaledHeight) / 2;
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
matrix.postTranslate(dx, dy);
canvas.drawBitmap(source, matrix, null);
return dest;
}
int dstWidth = 100;
int dstHeight = 100;
boolean doFilter = true;
Bitmap scaledBitmap = Bitmap.createScaledBitmap(src, dstWidth, dstHeight, doFilter);
Made a few modifications to the code from wsanville..and it worked for me
Note that I am using the minimum scale (taking what is the least, so that the whole bitmap can be rendered in the screen..if I take max, then it might go beyond the screen
int sourceWidth = mBitmap.getWidth();
int sourceHeight = mBitmap.getHeight();
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.min(xScale, yScale);
//get the resulting size after scaling
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
//figure out where we should translate to
float dx = (newWidth - scaledWidth) / 2;
float dy = (newHeight - scaledHeight) / 2;
Matrix defToScreenMatrix = new Matrix();
defToScreenMatrix.postScale(scale, scale);
defToScreenMatrix.postTranslate(dx, dy);
mBitmap = Bitmap.createBitmap(mBitmap, 0, 0, sourceWidth, sourceHeight, defToScreenMatrix, false);
I have an already decoded bitmap that I would like to temporarily scale before drawing it on a canvas. So decoding a file and setting the size before is out of the question. I would like to keep the size of the existing bitmap and just scale it to be smaller before drawing it on the canvas. Is this posible?
using Matrix postScale(sx, sy, px, py) scales it correctly but doesn't position it right. And canvas.drawBitmap doesn't have an option with matrix and x & y position from what I can see.
Any suggestions?
Here is the code:
public static Bitmap scaleBitmap(Bitmap bitmap, int width, int height) {
final int bitmapWidth = bitmap.getWidth();
final int bitmapHeight = bitmap.getHeight();
final float scale = Math.min((float) width / (float) bitmapWidth,
(float) height / (float) bitmapHeight);
final int scaledWidth = (int) (bitmapWidth * scale);
final int scaledHeight = (int) (bitmapHeight * scale);
final Bitmap decoded = Bitmap.createScaledBitmap(bitmap, scaledWidth, scaledHeight, true);
final Canvas canvas = new Canvas(decoded);
return decoded;
}
Please note: Pass the bitmap to scale and it's new height and width.
I've been trying this for some time, I would like to create a wallpaper from a Bitmap. Let's say the desired wallpaper size is 320x480, and the source image size is 2048x2048.
I'm not sure whether crop-to-fit is the right term, but what I would like to achieve is to get most part of the picture that has the equal ratio as the desired wallpaper size (320x480).
So in this case, I would like to get 2048x1365 or (1365.333... to be exact) from the source Bitmap, and scale it down to 320x480.
The technique that I have tried is:
1) Crop the Bitmap into 2048x1365 first
bm = Bitmap.createBitmap(bm, xOffset, yOffset, 2048, 1365);
2) Scale it down to 320x480
bm = Bitmap.createScaledBitmap(bm, 320, 480, false);
which produced OutOfMemory error.
Is there any way to achieve this?
Regards,
dezull
Thanks to open source, I found the answer from Android Gallery source code here at line 230 :-D
croppedImage = Bitmap.createBitmap(mOutputX, mOutputY, Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(croppedImage);
Rect srcRect = mCrop.getCropRect();
Rect dstRect = new Rect(0, 0, mOutputX, mOutputY);
int dx = (srcRect.width() - dstRect.width()) / 2;
int dy = (srcRect.height() - dstRect.height()) / 2;
// If the srcRect is too big, use the center part of it.
srcRect.inset(Math.max(0, dx), Math.max(0, dy));
// If the dstRect is too big, use the center part of it.
dstRect.inset(Math.max(0, -dx), Math.max(0, -dy));
// Draw the cropped bitmap in the center
canvas.drawBitmap(mBitmap, srcRect, dstRect, null);
I know this is an incredibly late reply, but something like this maybe:
public static Bitmap scaleCropToFit(Bitmap original, int targetWidth, int targetHeight){
//Need to scale the image, keeping the aspect ration first
int width = original.getWidth();
int height = original.getHeight();
float widthScale = (float) targetWidth / (float) width;
float heightScale = (float) targetHeight / (float) height;
float scaledWidth;
float scaledHeight;
int startY = 0;
int startX = 0;
if (widthScale > heightScale) {
scaledWidth = targetWidth;
scaledHeight = height * widthScale;
//crop height by...
startY = (int) ((scaledHeight - targetHeight) / 2);
} else {
scaledHeight = targetHeight;
scaledWidth = width * heightScale;
//crop width by..
startX = (int) ((scaledWidth - targetWidth) / 2);
}
Bitmap scaledBitmap = Bitmap.createScaledBitmap(original, (int) scaledWidth, (int) scaledHeight, true);
Bitmap resizedBitmap = Bitmap.createBitmap(scaledBitmap, startX, startY, targetWidth, targetHeight);
return resizedBitmap;
}
here is an answer that gets you most of the way there:
How to crop an image in android?