RMMapTiledLayerView SnapshotRenderer should not be limited by tileSource.minZoom && zoom <= tileSource.maxZoom

[jvieten]

I could provide a patch but do not know how to submit it?

RMMapTiledLayerView should use code from the "tries to return lower zoom level tiles if a tile cannot be found" section (RMMapTiledLayerView line 208) to provide an image even if the zoom factor is beyond the saved tileSource 's maxZoom

[incanus]

This functionality is called overzooming and adding it to snapshotting is an enhancement. Relatively low priority right now but will track in this ticket.

[jvieten]

Thank you so much! Its fun to have one's comments being at least considered. just in case here is what I am trying out:

diff --git a/MapView/Map/RMMapTiledLayerView.m b/MapView/Map/RMMapTiledLayerView.m
index f898f31..62d8ffa 100644
--- a/MapView/Map/RMMapTiledLayerView.m
+++ b/MapView/Map/RMMapTiledLayerView.m
@@ -91,6 +91,53 @@
     self.contentScaleFactor = 1.0f;
 }

+-(UIImage*) overzoomTileImage:(short) zoom column:(int) x row:(int)y
+{
+       UIImage *tileImage = nil;
+       int currentTileDepth = 1, currentZoom = zoom - currentTileDepth;
+       while(currentZoom >_tileSource.maxZoom)
+       {
+               currentZoom = zoom - ++currentTileDepth;
+       }
+               
+       
+       // tries to return lower zoom level tiles if a tile cannot be found
+       while ( !tileImage && currentZoom >= _tileSource.minZoom && currentTileDepth <= _mapView.missingTilesDepth)
+       {
+               float nextX = x / powf(2.0, (float)currentTileDepth),
+               nextY = y / powf(2.0, (float)currentTileDepth);
+               float nextTileX = floor(nextX),
+               nextTileY = floor(nextY);
+               tileImage = [_tileSource imageForTile:RMTileMake((int)nextTileX, (int)nextTileY, currentZoom) inCache:[_mapView tileCache]];
+               
+               if (IS_VALID_TILE_IMAGE(tileImage))
+               {
+                       // crop
+                       float cropSize = 1.0 / powf(2.0, (float)currentTileDepth);
+                       
+                       CGRect cropBounds = CGRectMake(tileImage.size.width * (nextX - nextTileX),
+                                                                                  tileImage.size.height * (nextY - nextTileY),
+                                                                                  tileImage.size.width * cropSize,
+                                                                                  tileImage.size.height * cropSize);
+                       
+                       CGImageRef imageRef = CGImageCreateWithImageInRect([tileImage CGImage], cropBounds);
+                       tileImage = [UIImage imageWithCGImage:imageRef];
+                       CGImageRelease(imageRef);
+                       
+                       break;
+               }
+               else
+               {
+                       tileImage = nil;
+               }
+               
+               currentTileDepth++;
+               currentZoom = zoom - currentTileDepth;
+       }
+       return tileImage;
+
+}
+
 - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context
 {
     CGRect rect   = CGContextGetClipBoundingBox(context);
@@ -111,7 +158,7 @@

 //        NSLog(@"Tiles from x1:%d, y1:%d to x2:%d, y2:%d @ zoom %d", x1, y1, x2, y2, zoom);

-        if (zoom >= _tileSource.minZoom && zoom <= _tileSource.maxZoom)
+        if (zoom >= _tileSource.minZoom)
         {
             UIGraphicsPushContext(context);
 - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context
 {
     CGRect rect   = CGContextGetClipBoundingBox(context);
@@ -111,7 +158,7 @@

 //        NSLog(@"Tiles from x1:%d, y1:%d to x2:%d, y2:%d @ zoom %d", x1, y1, x2, y2, zoom);

-        if (zoom >= _tileSource.minZoom && zoom <= _tileSource.maxZoom)
+        if (zoom >= _tileSource.minZoom)
         {
             UIGraphicsPushContext(context);

@@ -119,8 +166,12 @@
             {
                 for (int y=y1; y<=y2; ++y)
                 {
-                    UIImage *tileImage = [_tileSource imageForTile:RMTileMake(x, y, zoom) inCache:[_mapView tileCache]];
-
+                    UIImage *tileImage =  nil;
+                                       if(zoom <= _tileSource.maxZoom)
+                                               tileImage = [_tileSource imageForTile:RMTileMake(x, y, zoom) inCache:[_mapView tileCache]];
+                                       else
+                                               tileImage = [self overzoomTileImage:zoom column:x row:y];
+                                       
                     if (IS_VALID_TILE_IMAGE(tileImage))
                         [tileImage drawInRect:CGRectMake(x * rectSize, y * rectSize, rectSize, rectSize)];
                 }
@@ -203,42 +254,7 @@
             }
             else
             {
-                NSUInteger currentTileDepth = 1, currentZoom = zoom - currentTileDepth;
-
-                // tries to return lower zoom level tiles if a tile cannot be found
-                while ( !tileImage && currentZoom >= _tileSource.minZoom && currentTileDepth <= _mapView.missingTilesDepth)
-                {
-                    float nextX = x / powf(2.0, (float)currentTileDepth),
-                          nextY = y / powf(2.0, (float)currentTileDepth);
-                    float nextTileX = floor(nextX),
-                          nextTileY = floor(nextY);
-
-                    tileImage = [_tileSource imageForTile:RMTileMake((int)nextTileX, (int)nextTileY, currentZoom) inCache:[_mapView tileCache]];
-
-                    if (IS_VALID_TILE_IMAGE(tileImage))
-                    {
-                        // crop
-                        float cropSize = 1.0 / powf(2.0, (float)currentTileDepth);
-
-                        CGRect cropBounds = CGRectMake(tileImage.size.width * (nextX - nextTileX),
-                                                       tileImage.size.height * (nextY - nextTileY),
-                                                       tileImage.size.width * cropSize,
-                                                       tileImage.size.height * cropSize);
-
-                        CGImageRef imageRef = CGImageCreateWithImageInRect([tileImage CGImage], cropBounds);
-                        tileImage = [UIImage imageWithCGImage:imageRef];
-                        CGImageRelease(imageRef);
-
-                        break;
-                    }
-                    else
-                    {
-                        tileImage = nil;
-                    }
-
-                    currentTileDepth++;
-                    currentZoom = zoom - currentTileDepth;
-                }
+                tileImage = [self overzoomTileImage:zoom column:x row:y];