src.com.android.launcher3.icons.IconNormalizer Maven / Gradle / Ivy
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.launcher3.icons;
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.graphics.drawable.AdaptiveIconDrawable;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.util.Log;
import java.nio.ByteBuffer;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
public class IconNormalizer {
private static final String TAG = "IconNormalizer";
private static final boolean DEBUG = false;
// Ratio of icon visible area to full icon size for a square shaped icon
private static final float MAX_SQUARE_AREA_FACTOR = 375.0f / 576;
// Ratio of icon visible area to full icon size for a circular shaped icon
private static final float MAX_CIRCLE_AREA_FACTOR = 380.0f / 576;
private static final float CIRCLE_AREA_BY_RECT = (float) Math.PI / 4;
// Slope used to calculate icon visible area to full icon size for any generic shaped icon.
private static final float LINEAR_SCALE_SLOPE =
(MAX_CIRCLE_AREA_FACTOR - MAX_SQUARE_AREA_FACTOR) / (1 - CIRCLE_AREA_BY_RECT);
private static final int MIN_VISIBLE_ALPHA = 40;
// Shape detection related constants
private static final float BOUND_RATIO_MARGIN = .05f;
private static final float PIXEL_DIFF_PERCENTAGE_THRESHOLD = 0.005f;
private static final float SCALE_NOT_INITIALIZED = 0;
// Ratio of the diameter of an normalized circular icon to the actual icon size.
public static final float ICON_VISIBLE_AREA_FACTOR = 0.92f;
private final int mMaxSize;
private final Bitmap mBitmap;
private final Canvas mCanvas;
private final Paint mPaintMaskShape;
private final Paint mPaintMaskShapeOutline;
private final byte[] mPixels;
private final RectF mAdaptiveIconBounds;
private float mAdaptiveIconScale;
private boolean mEnableShapeDetection;
// for each y, stores the position of the leftmost x and the rightmost x
private final float[] mLeftBorder;
private final float[] mRightBorder;
private final Rect mBounds;
private final Path mShapePath;
private final Matrix mMatrix;
/** package private **/
IconNormalizer(Context context, int iconBitmapSize, boolean shapeDetection) {
// Use twice the icon size as maximum size to avoid scaling down twice.
mMaxSize = iconBitmapSize * 2;
mBitmap = Bitmap.createBitmap(mMaxSize, mMaxSize, Bitmap.Config.ALPHA_8);
mCanvas = new Canvas(mBitmap);
mPixels = new byte[mMaxSize * mMaxSize];
mLeftBorder = new float[mMaxSize];
mRightBorder = new float[mMaxSize];
mBounds = new Rect();
mAdaptiveIconBounds = new RectF();
mPaintMaskShape = new Paint();
mPaintMaskShape.setColor(Color.RED);
mPaintMaskShape.setStyle(Paint.Style.FILL);
mPaintMaskShape.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.XOR));
mPaintMaskShapeOutline = new Paint();
mPaintMaskShapeOutline.setStrokeWidth(
2 * context.getResources().getDisplayMetrics().density);
mPaintMaskShapeOutline.setStyle(Paint.Style.STROKE);
mPaintMaskShapeOutline.setColor(Color.BLACK);
mPaintMaskShapeOutline.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
mShapePath = new Path();
mMatrix = new Matrix();
mAdaptiveIconScale = SCALE_NOT_INITIALIZED;
mEnableShapeDetection = shapeDetection;
}
private static float getScale(float hullArea, float boundingArea, float fullArea) {
float hullByRect = hullArea / boundingArea;
float scaleRequired;
if (hullByRect < CIRCLE_AREA_BY_RECT) {
scaleRequired = MAX_CIRCLE_AREA_FACTOR;
} else {
scaleRequired = MAX_SQUARE_AREA_FACTOR + LINEAR_SCALE_SLOPE * (1 - hullByRect);
}
float areaScale = hullArea / fullArea;
// Use sqrt of the final ratio as the images is scaled across both width and height.
return areaScale > scaleRequired ? (float) Math.sqrt(scaleRequired / areaScale) : 1;
}
/**
* @param d Should be AdaptiveIconDrawable
* @param size Canvas size to use
*/
@TargetApi(Build.VERSION_CODES.O)
public static float normalizeAdaptiveIcon(Drawable d, int size, @Nullable RectF outBounds) {
Rect tmpBounds = new Rect(d.getBounds());
d.setBounds(0, 0, size, size);
Path path = ((AdaptiveIconDrawable) d).getIconMask();
Region region = new Region();
region.setPath(path, new Region(0, 0, size, size));
Rect hullBounds = region.getBounds();
int hullArea = GraphicsUtils.getArea(region);
if (outBounds != null) {
float sizeF = size;
outBounds.set(
hullBounds.left / sizeF,
hullBounds.top / sizeF,
1 - (hullBounds.right / sizeF),
1 - (hullBounds.bottom / sizeF));
}
d.setBounds(tmpBounds);
return getScale(hullArea, hullArea, size * size);
}
/**
* Returns if the shape of the icon is same as the path.
* For this method to work, the shape path bounds should be in [0,1]x[0,1] bounds.
*/
private boolean isShape(Path maskPath) {
// Condition1:
// If width and height of the path not close to a square, then the icon shape is
// not same as the mask shape.
float iconRatio = ((float) mBounds.width()) / mBounds.height();
if (Math.abs(iconRatio - 1) > BOUND_RATIO_MARGIN) {
if (DEBUG) {
Log.d(TAG, "Not same as mask shape because width != height. " + iconRatio);
}
return false;
}
// Condition 2:
// Actual icon (white) and the fitted shape (e.g., circle)(red) XOR operation
// should generate transparent image, if the actual icon is equivalent to the shape.
// Fit the shape within the icon's bounding box
mMatrix.reset();
mMatrix.setScale(mBounds.width(), mBounds.height());
mMatrix.postTranslate(mBounds.left, mBounds.top);
maskPath.transform(mMatrix, mShapePath);
// XOR operation
mCanvas.drawPath(mShapePath, mPaintMaskShape);
// DST_OUT operation around the mask path outline
mCanvas.drawPath(mShapePath, mPaintMaskShapeOutline);
// Check if the result is almost transparent
return isTransparentBitmap();
}
/**
* Used to determine if certain the bitmap is transparent.
*/
private boolean isTransparentBitmap() {
ByteBuffer buffer = ByteBuffer.wrap(mPixels);
buffer.rewind();
mBitmap.copyPixelsToBuffer(buffer);
int y = mBounds.top;
// buffer position
int index = y * mMaxSize;
// buffer shift after every row, width of buffer = mMaxSize
int rowSizeDiff = mMaxSize - mBounds.right;
int sum = 0;
for (; y < mBounds.bottom; y++) {
index += mBounds.left;
for (int x = mBounds.left; x < mBounds.right; x++) {
if ((mPixels[index] & 0xFF) > MIN_VISIBLE_ALPHA) {
sum++;
}
index++;
}
index += rowSizeDiff;
}
float percentageDiffPixels = ((float) sum) / (mBounds.width() * mBounds.height());
return percentageDiffPixels < PIXEL_DIFF_PERCENTAGE_THRESHOLD;
}
/**
* Returns the amount by which the {@param d} should be scaled (in both dimensions) so that it
* matches the design guidelines for a launcher icon.
*
* We first calculate the convex hull of the visible portion of the icon.
* This hull then compared with the bounding rectangle of the hull to find how closely it
* resembles a circle and a square, by comparing the ratio of the areas. Note that this is not an
* ideal solution but it gives satisfactory result without affecting the performance.
*
* This closeness is used to determine the ratio of hull area to the full icon size.
* Refer {@link #MAX_CIRCLE_AREA_FACTOR} and {@link #MAX_SQUARE_AREA_FACTOR}
*
* @param outBounds optional rect to receive the fraction distance from each edge.
*/
public synchronized float getScale(@NonNull Drawable d, @Nullable RectF outBounds,
@Nullable Path path, @Nullable boolean[] outMaskShape) {
if (d instanceof AdaptiveIconDrawable) {
if (mAdaptiveIconScale == SCALE_NOT_INITIALIZED) {
mAdaptiveIconScale = normalizeAdaptiveIcon(d, mMaxSize, mAdaptiveIconBounds);
}
if (outBounds != null) {
outBounds.set(mAdaptiveIconBounds);
}
return mAdaptiveIconScale;
}
int width = d.getIntrinsicWidth();
int height = d.getIntrinsicHeight();
if (width <= 0 || height <= 0) {
width = width <= 0 || width > mMaxSize ? mMaxSize : width;
height = height <= 0 || height > mMaxSize ? mMaxSize : height;
} else if (width > mMaxSize || height > mMaxSize) {
int max = Math.max(width, height);
width = mMaxSize * width / max;
height = mMaxSize * height / max;
}
mBitmap.eraseColor(Color.TRANSPARENT);
d.setBounds(0, 0, width, height);
d.draw(mCanvas);
ByteBuffer buffer = ByteBuffer.wrap(mPixels);
buffer.rewind();
mBitmap.copyPixelsToBuffer(buffer);
// Overall bounds of the visible icon.
int topY = -1;
int bottomY = -1;
int leftX = mMaxSize + 1;
int rightX = -1;
// Create border by going through all pixels one row at a time and for each row find
// the first and the last non-transparent pixel. Set those values to mLeftBorder and
// mRightBorder and use -1 if there are no visible pixel in the row.
// buffer position
int index = 0;
// buffer shift after every row, width of buffer = mMaxSize
int rowSizeDiff = mMaxSize - width;
// first and last position for any row.
int firstX, lastX;
for (int y = 0; y < height; y++) {
firstX = lastX = -1;
for (int x = 0; x < width; x++) {
if ((mPixels[index] & 0xFF) > MIN_VISIBLE_ALPHA) {
if (firstX == -1) {
firstX = x;
}
lastX = x;
}
index++;
}
index += rowSizeDiff;
mLeftBorder[y] = firstX;
mRightBorder[y] = lastX;
// If there is at least one visible pixel, update the overall bounds.
if (firstX != -1) {
bottomY = y;
if (topY == -1) {
topY = y;
}
leftX = Math.min(leftX, firstX);
rightX = Math.max(rightX, lastX);
}
}
if (topY == -1 || rightX == -1) {
// No valid pixels found. Do not scale.
return 1;
}
convertToConvexArray(mLeftBorder, 1, topY, bottomY);
convertToConvexArray(mRightBorder, -1, topY, bottomY);
// Area of the convex hull
float area = 0;
for (int y = 0; y < height; y++) {
if (mLeftBorder[y] <= -1) {
continue;
}
area += mRightBorder[y] - mLeftBorder[y] + 1;
}
mBounds.left = leftX;
mBounds.right = rightX;
mBounds.top = topY;
mBounds.bottom = bottomY;
if (outBounds != null) {
outBounds.set(((float) mBounds.left) / width, ((float) mBounds.top) / height,
1 - ((float) mBounds.right) / width,
1 - ((float) mBounds.bottom) / height);
}
if (outMaskShape != null && mEnableShapeDetection && outMaskShape.length > 0) {
outMaskShape[0] = isShape(path);
}
// Area of the rectangle required to fit the convex hull
float rectArea = (bottomY + 1 - topY) * (rightX + 1 - leftX);
return getScale(area, rectArea, width * height);
}
/**
* Modifies {@param xCoordinates} to represent a convex border. Fills in all missing values
* (except on either ends) with appropriate values.
* @param xCoordinates map of x coordinate per y.
* @param direction 1 for left border and -1 for right border.
* @param topY the first Y position (inclusive) with a valid value.
* @param bottomY the last Y position (inclusive) with a valid value.
*/
private static void convertToConvexArray(
float[] xCoordinates, int direction, int topY, int bottomY) {
int total = xCoordinates.length;
// The tangent at each pixel.
float[] angles = new float[total - 1];
int first = topY; // First valid y coordinate
int last = -1; // Last valid y coordinate which didn't have a missing value
float lastAngle = Float.MAX_VALUE;
for (int i = topY + 1; i <= bottomY; i++) {
if (xCoordinates[i] <= -1) {
continue;
}
int start;
if (lastAngle == Float.MAX_VALUE) {
start = first;
} else {
float currentAngle = (xCoordinates[i] - xCoordinates[last]) / (i - last);
start = last;
// If this position creates a concave angle, keep moving up until we find a
// position which creates a convex angle.
if ((currentAngle - lastAngle) * direction < 0) {
while (start > first) {
start --;
currentAngle = (xCoordinates[i] - xCoordinates[start]) / (i - start);
if ((currentAngle - angles[start]) * direction >= 0) {
break;
}
}
}
}
// Reset from last check
lastAngle = (xCoordinates[i] - xCoordinates[start]) / (i - start);
// Update all the points from start.
for (int j = start; j < i; j++) {
angles[j] = lastAngle;
xCoordinates[j] = xCoordinates[start] + lastAngle * (j - start);
}
last = i;
}
}
/**
* @return The diameter of the normalized circle that fits inside of the square (size x size).
*/
public static int getNormalizedCircleSize(int size) {
float area = size * size * MAX_CIRCLE_AREA_FACTOR;
return (int) Math.round(Math.sqrt((4 * area) / Math.PI));
}
}
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