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package com.android.launcher3.folder;
public class ClippedFolderIconLayoutRule implements FolderIcon.PreviewLayoutRule {
static final int MAX_NUM_ITEMS_IN_PREVIEW = 4;
private static final int MIN_NUM_ITEMS_IN_PREVIEW = 2;
private static final int MAX_NUM_ITEMS_PER_ROW = 2;
final float MIN_SCALE = 0.48f;
final float MAX_SCALE = 0.58f;
final float MAX_RADIUS_DILATION = 0.15f;
final float ITEM_RADIUS_SCALE_FACTOR = 1.33f;
private float[] mTmpPoint = new float[2];
private float mAvailableSpace;
private float mRadius;
private float mIconSize;
private boolean mIsRtl;
private float mBaselineIconScale;
@Override
public void init(int availableSpace, int intrinsicIconSize, boolean rtl) {
mAvailableSpace = availableSpace;
mRadius = ITEM_RADIUS_SCALE_FACTOR * availableSpace / 2f;
mIconSize = intrinsicIconSize;
mIsRtl = rtl;
mBaselineIconScale = availableSpace / (intrinsicIconSize * 1f);
}
@Override
public FolderIcon.PreviewItemDrawingParams computePreviewItemDrawingParams(int index,
int curNumItems, FolderIcon.PreviewItemDrawingParams params) {
float totalScale = scaleForItem(index, curNumItems);
float transX;
float transY;
float overlayAlpha = 0;
// Items beyond those displayed in the preview are animated to the center
if (index >= MAX_NUM_ITEMS_IN_PREVIEW) {
transX = transY = mAvailableSpace / 2 - (mIconSize * totalScale) / 2;
} else {
getPosition(index, curNumItems, mTmpPoint);
transX = mTmpPoint[0];
transY = mTmpPoint[1];
}
if (params == null) {
params = new FolderIcon.PreviewItemDrawingParams(transX, transY, totalScale, overlayAlpha);
} else {
params.update(transX, transY, totalScale);
params.overlayAlpha = overlayAlpha;
}
return params;
}
private void getPosition(int index, int curNumItems, float[] result) {
// The case of two items is homomorphic to the case of one.
curNumItems = Math.max(curNumItems, 2);
// We model the preview as a circle of items starting in the appropriate piece of the
// upper left quadrant (to achieve horizontal and vertical symmetry).
double theta0 = mIsRtl ? 0 : Math.PI;
// In RTL we go counterclockwise
int direction = mIsRtl ? 1 : -1;
double thetaShift = 0;
if (curNumItems == 3) {
thetaShift = Math.PI / 6;
} else if (curNumItems == 4) {
thetaShift = Math.PI / 4;
}
theta0 += direction * thetaShift;
// We want the items to appear in reading order. For the case of 1, 2 and 3 items, this
// is natural for the circular model. With 4 items, however, we need to swap the 3rd and
// 4th indices to achieve reading order.
if (curNumItems == 4 && index == 3) {
index = 2;
} else if (curNumItems == 4 && index == 2) {
index = 3;
}
// We bump the radius up between 0 and MAX_RADIUS_DILATION % as the number of items increase
float radius = mRadius * (1 + MAX_RADIUS_DILATION * (curNumItems -
MIN_NUM_ITEMS_IN_PREVIEW) / (MAX_NUM_ITEMS_IN_PREVIEW - MIN_NUM_ITEMS_IN_PREVIEW));
double theta = theta0 + index * (2 * Math.PI / curNumItems) * direction;
float halfIconSize = (mIconSize * scaleForItem(index, curNumItems)) / 2;
// Map the location along the circle, and offset the coordinates to represent the center
// of the icon, and to be based from the top / left of the preview area. The y component
// is inverted to match the coordinate system.
result[0] = mAvailableSpace / 2 + (float) (radius * Math.cos(theta) / 2) - halfIconSize;
result[1] = mAvailableSpace / 2 + (float) (- radius * Math.sin(theta) / 2) - halfIconSize;
}
@Override
public float scaleForItem(int index, int numItems) {
// Scale is determined by the number of items in the preview.
float scale = 1f;
if (numItems <= 2) {
scale = MAX_SCALE;
} else if (numItems == 3) {
scale = (MAX_SCALE + MIN_SCALE) / 2;
} else {
scale = MIN_SCALE;
}
return scale * mBaselineIconScale;
}
@Override
public float getIconSize() {
return mIconSize;
}
@Override
public int maxNumItems() {
return MAX_NUM_ITEMS_IN_PREVIEW;
}
@Override
public boolean clipToBackground() {
return true;
}
}
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