1 package com.android.launcher3.folder; 2 3 import android.graphics.Path; 4 import android.graphics.Point; 5 6 import com.android.launcher3.DeviceProfile; 7 import com.android.launcher3.LauncherAppState; 8 import com.android.launcher3.Utilities; 9 10 public class ClippedFolderIconLayoutRule implements FolderIcon.PreviewLayoutRule { 11 12 static final int MAX_NUM_ITEMS_IN_PREVIEW = 4; 13 private static final int MIN_NUM_ITEMS_IN_PREVIEW = 2; 14 15 final float MIN_SCALE = 0.48f; 16 final float MAX_SCALE = 0.58f; 17 final float MAX_RADIUS_DILATION = 0.15f; 18 final float ITEM_RADIUS_SCALE_FACTOR = 1.33f; 19 20 private float[] mTmpPoint = new float[2]; 21 22 private float mAvailableSpace; 23 private float mRadius; 24 private float mIconSize; 25 private boolean mIsRtl; 26 private float mBaselineIconScale; 27 28 @Override 29 public void init(int availableSpace, int intrinsicIconSize, boolean rtl) { 30 mAvailableSpace = availableSpace; 31 mRadius = ITEM_RADIUS_SCALE_FACTOR * availableSpace / 2f; 32 mIconSize = intrinsicIconSize; 33 mIsRtl = rtl; 34 mBaselineIconScale = availableSpace / (intrinsicIconSize * 1f); 35 } 36 37 @Override 38 public FolderIcon.PreviewItemDrawingParams computePreviewItemDrawingParams(int index, 39 int curNumItems, FolderIcon.PreviewItemDrawingParams params) { 40 41 float totalScale = scaleForNumItems(curNumItems); 42 float transX; 43 float transY; 44 float overlayAlpha = 0; 45 46 // Items beyond those displayed in the preview are animated to the center 47 if (index >= MAX_NUM_ITEMS_IN_PREVIEW) { 48 transX = transY = mAvailableSpace / 2 - (mIconSize * totalScale) / 2; 49 } else { 50 getPosition(index, curNumItems, mTmpPoint); 51 transX = mTmpPoint[0]; 52 transY = mTmpPoint[1]; 53 } 54 55 if (params == null) { 56 params = new FolderIcon.PreviewItemDrawingParams(transX, transY, totalScale, overlayAlpha); 57 } else { 58 params.update(transX, transY, totalScale); 59 params.overlayAlpha = overlayAlpha; 60 } 61 return params; 62 } 63 64 private void getPosition(int index, int curNumItems, float[] result) { 65 // The case of two items is homomorphic to the case of one. 66 curNumItems = Math.max(curNumItems, 2); 67 68 // We model the preview as a circle of items starting in the appropriate piece of the 69 // upper left quadrant (to achieve horizontal and vertical symmetry). 70 double theta0 = mIsRtl ? 0 : Math.PI; 71 72 // In RTL we go counterclockwise 73 int direction = mIsRtl ? 1 : -1; 74 75 double thetaShift = 0; 76 if (curNumItems == 3) { 77 thetaShift = Math.PI / 6; 78 } else if (curNumItems == 4) { 79 thetaShift = Math.PI / 4; 80 } 81 theta0 += direction * thetaShift; 82 83 // We want the items to appear in reading order. For the case of 1, 2 and 3 items, this 84 // is natural for the circular model. With 4 items, however, we need to swap the 3rd and 85 // 4th indices to achieve reading order. 86 if (curNumItems == 4 && index == 3) { 87 index = 2; 88 } else if (curNumItems == 4 && index == 2) { 89 index = 3; 90 } 91 92 // We bump the radius up between 0 and MAX_RADIUS_DILATION % as the number of items increase 93 float radius = mRadius * (1 + MAX_RADIUS_DILATION * (curNumItems - 94 MIN_NUM_ITEMS_IN_PREVIEW) / (MAX_NUM_ITEMS_IN_PREVIEW - MIN_NUM_ITEMS_IN_PREVIEW)); 95 double theta = theta0 + index * (2 * Math.PI / curNumItems) * direction; 96 97 float halfIconSize = (mIconSize * scaleForNumItems(curNumItems)) / 2; 98 99 // Map the location along the circle, and offset the coordinates to represent the center 100 // of the icon, and to be based from the top / left of the preview area. The y component 101 // is inverted to match the coordinate system. 102 result[0] = mAvailableSpace / 2 + (float) (radius * Math.cos(theta) / 2) - halfIconSize; 103 result[1] = mAvailableSpace / 2 + (float) (- radius * Math.sin(theta) / 2) - halfIconSize; 104 105 } 106 107 private float scaleForNumItems(int numItems) { 108 float scale = 1f; 109 if (numItems <= 2) { 110 scale = MAX_SCALE; 111 } else if (numItems == 3) { 112 scale = (MAX_SCALE + MIN_SCALE) / 2; 113 } else { 114 scale = MIN_SCALE; 115 } 116 117 return scale * mBaselineIconScale; 118 } 119 120 @Override 121 public int numItems() { 122 return MAX_NUM_ITEMS_IN_PREVIEW; 123 } 124 125 @Override 126 public boolean clipToBackground() { 127 return true; 128 } 129 130 } 131