Allow pane height to shrink when setting topology

A recent CL added a feature to prevent the pane height from shrinking to
stop widgets from moving around. This is actually not a great experience
because a temporary state can keep the pane height very tall and
increase scrolling.

Flag: com.android.settings.flags.display_topology_pane_in_display_list
Bug: b/352648432
Test: change topology to be vertically shorter and verify the pane height shrinks
Change-Id: Ic48bfecea083a45c702c8719e3c93ceba55ae872

src/com/android/settings/connecteddevice/display/DisplayTopology.kt

@@ -73,9 +73,6 @@ fun Float.atLeast(n: Number): Float = max(this, n.toFloat())
  * position. In practice the origin will be the upper-left coordinate of the primary display.
  *
  * @param paneWidth width of the pane in view coordinates
- * @param minPaneHeight smallest allowed height of the pane in view coordinates. This will not
- *                      affect the block ratio, but only the final height of the pane and the
- *                      position of the display bounds' center.
  * @param minEdgeLength the smallest length permitted of a display block. This should be set based
  *                      on accessibility requirements, but also accounting for padding that appears
  *                      around each button.
@@ -85,7 +82,7 @@ fun Float.atLeast(n: Number): Float = max(this, n.toFloat())
  * @param displaysPos the absolute topology coordinates for each display in the topology.
  */
 class TopologyScale(
-        paneWidth: Int, minPaneHeight: Float, minEdgeLength: Float, maxEdgeLength: Float,
+        paneWidth: Int, minEdgeLength: Float, maxEdgeLength: Float,
         displaysPos: Collection<RectF>) {
     /** Scale of block sizes to real-world display sizes. Should be less than 1. */
     val blockRatio: Float
@@ -124,12 +121,11 @@ class TopologyScale(
                 // requirements.
                 .atLeast(minEdgeLength / smallestDisplayDim)
 
-        paneHeight = minPaneHeight
+        // A tall pane is likely to result in more scrolling. So we
-                // A tall pane is likely to result in more scrolling. So we
+        // prevent the height from growing too large here, by limiting vertical padding to
-                // prevent the height from growing too large here, by limiting vertical padding to
+        // 1.5x of the minEdgeLength on each side. This keeps a comfortable amount of
-                // 1.5x of the minEdgeLength on each side. This keeps a comfortable amount of
+        // padding without it resulting in too much deadspace.
-                // padding without it resulting in too much deadspace.
+        paneHeight = blockRatio * displayBounds.height() + minEdgeLength * 3f
-                .atLeast(blockRatio * displayBounds.height() + minEdgeLength * 3f)
 
         // Set originPaneXY (the location of 0,0 in display space in the pane's coordinate system)
         // such that the display bounds rect is centered in the pane.
@@ -404,7 +400,7 @@ class DisplayTopologyPreference(context : Context)
         // pixels, and the display coordinates are in density-independent pixels.
         val dpi = injector.densityDpi
         val scaling = TopologyScale(
-                mPaneContent.width, minPaneHeight = mTopologyInfo?.scaling?.paneHeight ?: 0f,
+                mPaneContent.width,
                 minEdgeLength = DisplayTopology.dpToPx(60f, dpi),
                 maxEdgeLength = DisplayTopology.dpToPx(256f, dpi),
                 newBounds.map { it.second }.toList())

tests/robotests/src/com/android/settings/connecteddevice/display/TopologyScaleTest.kt

@@ -45,8 +45,7 @@ class TopologyScaleTest {
     @Test
     fun oneDisplay4to3Aspect() {
         val scale = TopologyScale(
-                /* paneWidth= */ 640, minPaneHeight = 0f,
+                paneWidth = 640, minEdgeLength = 48f, maxEdgeLength = 64f,
-                minEdgeLength = 48f, maxEdgeLength = 64f,
                 listOf(RectF(0f, 0f, 640f, 480f)))
 
         // blockRatio is is set in order to make the smallest display edge (480 dp) 48dp
@@ -62,24 +61,12 @@ class TopologyScaleTest {
                 PointF(640f, 240f) to scale.paneToDisplayCoor(352f, 96f),
             ),
             0.001f)
-
-        // Same as original scale but made taller with minPaneHeight.
-        // The paneHeight and origin coordinates are changed but the block ratio is the same.
-        val taller = TopologyScale(
-                /* paneWidth= */ 640, minPaneHeight = 155.0f,
-                minEdgeLength = 48f, maxEdgeLength = 64f,
-                listOf(RectF(0f, 0f, 640f, 480f)))
-
-        assertEquals(
-                "{TopologyScale blockRatio=0.100000 originPaneXY=288.0,72.0 paneHeight=192.0}",
-                "" + taller)
     }
 
     @Test
     fun twoUnalignedDisplays() {
         val scale = TopologyScale(
-                /* paneWidth= */ 300, minPaneHeight = 0f,
+                paneWidth = 300, minEdgeLength = 48f, maxEdgeLength = 96f,
-                minEdgeLength = 48f, maxEdgeLength = 96f,
                 listOf(RectF(0f, 0f, 1920f, 1200f), RectF(1920f, -300f, 3840f, 900f)))
 
         assertEquals(
@@ -97,8 +84,7 @@ class TopologyScaleTest {
     @Test
     fun twoDisplaysBlockRatioBumpedForGarSizeMinimumHorizontal() {
         val scale = TopologyScale(
-                /* paneWidth= */ 192, minPaneHeight = 0f,
+                paneWidth = 192, minEdgeLength = 48f, maxEdgeLength = 64f,
-                minEdgeLength = 48f, maxEdgeLength = 64f,
                 listOf(RectF(0f, 0f, 240f, 320f), RectF(-240f, -320f, 0f, 0f)))
 
         // blockRatio is higher than 0.05 in order to make the smallest display edge (240 dp) 48dp
@@ -118,8 +104,7 @@ class TopologyScaleTest {
     @Test
     fun paneVerticalPaddingSetByMinEdgeLength() {
         val scale = TopologyScale(
-                /* paneWidth= */ 300, minPaneHeight = 0f,
+                paneWidth = 300, minEdgeLength = 48f, maxEdgeLength = 80f,
-                minEdgeLength = 48f, maxEdgeLength = 80f,
                 listOf(
                         RectF(0f, 0f, 640f, 480f),
                         RectF(0f, 480f, 640f, 960f),
@@ -141,8 +126,7 @@ class TopologyScaleTest {
     @Test
     fun limitedByCustomMaxBlockRatio() {
         val scale = TopologyScale(
-                /* paneWidth= */ 300, minPaneHeight = 0f,
+                paneWidth = 300, minEdgeLength = 24f, maxEdgeLength = 77f,
-                minEdgeLength = 24f, maxEdgeLength = 77f,
                 listOf(
                         RectF(0f, 0f, 640f, 480f),
                         RectF(0f, 480f, 640f, 960f)))
@@ -161,8 +145,7 @@ class TopologyScaleTest {
     fun largeCustomMinEdgeLength() {
         // minBlockEdgeLength/minDisplayEdgeLength = 80/480 = 1/6, so the block ratio will be 1/6
         val scale = TopologyScale(
-                /* paneWidth= */ 300, minPaneHeight = 0f,
+                paneWidth = 300, minEdgeLength = 80f, maxEdgeLength = 100f,
-                minEdgeLength = 80f, maxEdgeLength = 100f,
                 listOf(
                         RectF(0f, 0f, 640f, 480f),
                         RectF(0f, 480f, 640f, 960f)))