DisplayTopology: fix erroneous attach-to-corner (5e3e0bc6) · Commits · e / os / android_frameworks_base

core/java/android/hardware/display/DisplayTopology.java

+27 −28

Original line number	Diff line number	Diff line
		@@ -201,10 +201,9 @@ public final class DisplayTopology implements Parcelable {
		// The optimal pair is the pair which has the smallest deviation. The deviation consists of
		// an x-axis component and a y-axis component, called xDeviation and yDeviation.
		//
		// The deviations are like distances but a little different. They are calculated in two
		// steps. The first step calculates both axes in a similar way. The next step compares the
		// two values and chooses which axis to attach along. Depending on which axis is chosen,
		// the deviation for one axis is updated. See below for details.
		// The deviations are like distances but a little different. When they are calculated, each
		// dimension is treated differently, depending on which edges (left+right or top+bottom) are
		// attached.
		while (!needsParent.isEmpty()) {
		double bestDist = Double.POSITIVE_INFINITY;
		TreeNode bestChild = null, bestParent = null;
		@@ -218,33 +217,32 @@ public final class DisplayTopology implements Parcelable {
		float parentRight = parentPos.x + parent.getWidth();
		float parentBottom = parentPos.y + parent.getHeight();

		// This is the smaller of the two ranges minus the amount of overlap shared
		// between them. The "amount of overlap" is negative if there is no overlap, but
		// this does not make a parenting ineligible, because we allow for attaching at
		// the corner and for floating point error. The overlap is more negative the
		// farther apart the closest corner pair is.
		//
		// For each axis, this calculates (SmallerRange - Overlap). If one range lies
		// completely in the other (or they are equal), the axis' deviation will be
		// zero.
		//
		// The "SmallerRange," which refers to smaller of the widths of the two rects,
		// or smaller of the heights of the two rects, is added to the deviation so that
		// a maximum overlap results in a deviation of zero.
		float xSmallerRange = Math.min(child.getWidth(), parent.getWidth());
		float ySmallerRange = Math.min(child.getHeight(), parent.getHeight());
		float xOverlap
		= Math.min(parentRight, childRight)
		- Math.max(parentPos.x, childPos.x);
		float yOverlap
		= Math.min(parentBottom, childBottom)
		- Math.max(parentPos.y, childPos.y);
		float xDeviation = xSmallerRange - xOverlap;
		float yDeviation = ySmallerRange - yOverlap;
		// The "amount of overlap" indicates how much of one display is within the other
		// (considering one axis only). It's zero if they only share an edge and
		// negative if they're away from each other.
		// A zero or negative overlap does not make a parenting ineligible, because we
		// allow for attaching at the corner and for floating point error.
		float xOverlap =
		Math.min(parentRight, childRight) - Math.max(parentPos.x, childPos.x);
		float yOverlap =
		Math.min(parentBottom, childBottom) - Math.max(parentPos.y, childPos.y);
		float xDeviation, yDeviation;

		float offset;
		int pos;
		if (xDeviation <= yDeviation) {
		if (Math.abs(xOverlap) > Math.abs(yOverlap)) {
		// Deviation in each dimension is a penalty in the potential parenting. To
		// get the X deviation, overlap is subtracted from the lesser width so that
		// a maximum overlap results in a deviation of zero.
		// Note that because xOverlap is subtracted from the lesser width, no
		// overlap in X becomes a penalty if we are attaching on the top+bottom
		// edges.
		//
		// The Y deviation is simply the distance from the clamping edges.
		//
		// Treatment of the X and Y deviations are swapped for
		// POSITION_LEFT/POSITION_RIGHT attachments in the "else" block below.
		xDeviation = Math.min(child.getWidth(), parent.getWidth()) - xOverlap;
		if (childPos.y < parentPos.y) {
		yDeviation = childBottom - parentPos.y;
		pos = POSITION_TOP;
		@@ -254,6 +252,7 @@ public final class DisplayTopology implements Parcelable {
		}
		offset = childPos.x - parentPos.x;
		} else {
		yDeviation = Math.min(child.getHeight(), parent.getHeight()) - yOverlap;
		if (childPos.x < parentPos.x) {
		xDeviation = childRight - parentPos.x;
		pos = POSITION_LEFT;

core/tests/coretests/src/android/hardware/display/DisplayTopologyTest.kt

+53 −1

Original line number	Diff line number	Diff line
		@@ -572,12 +572,64 @@ class DisplayTopologyTest {
		verifyDisplay(
		root.children[0], id = 1, width = 30f, height = 30f, POSITION_RIGHT, offset = 10f,
		noOfChildren = 1)
		// In the case of corner adjacency, we prefer a left/right attachment.
		verifyDisplay(
		root.children[0].children[0], id = 2, width = 29.5f, height = 30f, POSITION_BOTTOM,
		offset = 30f, noOfChildren = 0)
		}

		@Test
		fun rearrange_preferLessShiftInOverlapDimension() {
		val root = rearrangeRects(
		// '*' represents overlap
		// Clamping requires moving display 2 and 1 slightly to avoid overlap with 0. We should
		// shift the minimal amount to avoid overlap - e.g. display 2 shifts left (10 pixels)
		// rather than up (20 pixels).
		// 222
		// 22*00
		// 22*00
		// 0**1
		// 111
		// 111
		RectF(20f, 10f, 50f, 40f),
		RectF(30f, 30f, 60f, 60f),
		RectF(0f, 0f, 30f, 30f),
		)

		verifyDisplay(root, id = 0, width = 30f, height = 30f, noOfChildren = 2)
		verifyDisplay(
		root.children[0], id = 1, width = 30f, height = 30f, POSITION_BOTTOM, offset = 10f,
		noOfChildren = 0)
		verifyDisplay(
		root.children[1], id = 2, width = 30f, height = 30f, POSITION_LEFT, offset = -10f,
		noOfChildren = 0)
		}

		@Test
		fun rearrange_doNotAttachCornerForShortOverlapOnLongEdgeBottom() {
		val root = rearrangeRects(
		RectF(0f, 0f, 1920f, 1080f),
		RectF(1850f, 1070f, 3770f, 2150f),
		)

		verifyDisplay(root, id = 0, width = 1920f, height = 1080f, noOfChildren = 1)
		verifyDisplay(
		root.children[0], id = 1, width = 1920f, height = 1080f, POSITION_BOTTOM,
		offset = 1850f, noOfChildren = 0)
		}

		@Test
		fun rearrange_doNotAttachCornerForShortOverlapOnLongEdgeLeft() {
		val root = rearrangeRects(
		RectF(0f, 0f, 1080f, 1920f),
		RectF(-1070f, -1880f, 10f, 40f),
		)

		verifyDisplay(root, id = 0, width = 1080f, height = 1920f, noOfChildren = 1)
		verifyDisplay(
		root.children[0], id = 1, width = 1080f, height = 1920f, POSITION_LEFT,
		offset = -1880f, noOfChildren = 0)
		}

		@Test
		fun copy() {
		val display1 = DisplayTopology.TreeNode(/* displayId= / 1, / width= */ 200f,