Improve DEM tiles

Signed-off-by: Kyle Corry <[email protected]>

Author: kylecorry31

app/src/main/java/com/kylecorry/trail_sense/shared/dem/DEM.kt

@@ -167,9 +167,10 @@ object DEM {
             Color.rgb(gray, gray, gray)
         }
     ): Bitmap = onDefault {
+        val expandBy = 1
         val grid = getElevationGrid(bounds, resolution)
-        val height = grid.size
-        val width = grid[0].size
+        val width = grid[0].size - expandBy * 2
+        val height = grid.size - expandBy * 2
         val pixels = IntArray(height * width)
 
         try {
@@ -186,10 +187,10 @@ object DEM {
                 }
             }
 
-            for (y in grid.indices) {
-                for (x in grid[y].indices) {
+            for (y in expandBy .. grid.lastIndex - expandBy) {
+                for (x in expandBy .. grid[y].lastIndex - expandBy) {
                     val color = colorMap(grid[y][x].second, minElevation, maxElevation)
-                    pixels.set(x, y, width, color)
+                    pixels.set(x - expandBy, y - expandBy, width, color)
                 }
             }
             Bitmap.createBitmap(pixels, width, height, Bitmap.Config.RGB_565)
@@ -207,9 +208,10 @@ object DEM {
         samples: Int = 1,
         sampleSpacing: Float = 3f
     ): Bitmap = onDefault {
+        val expandBy = 1
         val grid = getElevationGrid(bounds, resolution)
-        val width = grid[0].size
-        val height = grid.size
+        val width = grid[0].size - expandBy * 2
+        val height = grid.size - expandBy * 2
         val pixels = IntArray(width * height)
 
         try {
@@ -231,8 +233,8 @@ object DEM {
             val cosZenith = cos(zenithRad)
             val sinZenith = sin(zenithRad)
 
-            for (y in grid.indices) {
-                for (x in grid[y].indices) {
+            for (y in expandBy .. grid.lastIndex - expandBy) {
+                for (x in expandBy .. grid[y].lastIndex - expandBy) {
                     val a = getElevation(x - 1, y - 1)
                     val b = getElevation(x, y - 1)
                     val c = getElevation(x + 1, y - 1)
@@ -263,7 +265,7 @@ object DEM {
                     }
 
                     val gray = hillshade.toInt().coerceIn(0, 255)
-                    pixels.set(x, y, width, Color.rgb(gray, gray, gray))
+                    pixels.set(x - expandBy, y - expandBy, width, Color.rgb(gray, gray, gray))
                 }
             }
             Bitmap.createBitmap(pixels, width, height, Bitmap.Config.RGB_565)

app/src/main/java/com/kylecorry/trail_sense/shared/dem/map_layers/ElevationLayer.kt

@@ -14,8 +14,6 @@ class ElevationLayer(taskRunner: MapLayerBackgroundTask2 = MapLayerBackgroundTas
     init {
         preRenderBitmaps = true
         loader.useFirstImageSize = true
-        loader.alwaysReloadTiles = true
-        loader.clearTileWhenNullResponse = false
     }
 
     fun setPreferences(prefs: ElevationMapLayerPreferences) {

app/src/main/java/com/kylecorry/trail_sense/shared/dem/map_layers/HillshadeLayer.kt

@@ -13,8 +13,6 @@ class HillshadeLayer(taskRunner: MapLayerBackgroundTask2 = MapLayerBackgroundTas
     init {
         preRenderBitmaps = true
         loader.useFirstImageSize = true
-        loader.alwaysReloadTiles = true
-        loader.clearTileWhenNullResponse = false
         alpha = 127
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             tilePaint.setBlendMode(BlendModeCompat.MULTIPLY)

app/src/main/java/com/kylecorry/trail_sense/shared/map_layers/tiles/TileLoader.kt

@@ -153,7 +153,11 @@ class TileLoader {
             synchronized(lock) {
                 if (clearTileWhenNullResponse || image != null) {
                     val old = tileCache[source.key]
-                    tileCache += source.key to listOfNotNull(image)
+                    if (image == null){
+                        tileCache -= source.key
+                    } else {
+                        tileCache += source.key to listOfNotNull(image)
+                    }
                     old?.forEach { it.recycle() }
                 }
             }

app/src/main/java/com/kylecorry/trail_sense/shared/map_layers/ui/layers/tiles/TileMapLayer.kt

@@ -162,7 +162,7 @@ abstract class TileMapLayer<T : ITileSourceSelector>(
 
             preRenderedBitmap = createBitmap(bitmapWidth, bitmapHeight)
             val mergeCanvas = Canvas(preRenderedBitmap!!)
-            mergeCanvas.drawColor(backgroundColor)
+            mergeCanvas.drawColor(Color.TRANSPARENT)
 
             // Render all tiles into the merged bitmap
             loader.tileCache.entries.sortedBy { it.key.z }.forEach { (tile, bitmaps) ->