Add support for JPEG tiles v1 NEEDS REVISION

Hanspeter Portner: 1
 Add support for JPEG tiles

 1 files changed, 2 insertions(+), 1 deletions(-)

[PATCH] Add support for JPEG tiles Export this patch

The tile server [1] I'd like to use only provides JPEG tiles and `mepo`
currently refuses to load anything else than PNGs.

As nothing else in the code seems to depend on the PNG format
specifically and SDL can handle any image type it supports, this change
just adds a check for JPEG images.

Tested with tile server [1] (zoom in to Switzerland to see something).

[1] https://wmts.geo.admin.ch/1.0.0/ch.swisstopo.pixelkarte-farbe/default/current/3857/%3$d/%1$d/%2$d.jpeg
---
 src/TileCache.zig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Miles Alan <m@milesalan.com>

4 months ago

Thanks for sending - and apologies for the extended delay for review,
been caught up in a few other things.

JPEG support sounds good to me & this mostly looks good. However, we
would also need to modify the other references in the code for JPEG
support as well.

In src/Mepo.zig:
  - We would replace IMG_INIT_PNG to be IMG_INIT_PNG | IMG_INIT_JPG

In src/TileCache.zig:
  - png_path fn would need to be replaced to support .png or .jpg
    - As is current design with patch we'd be writing JPG data to .png files
  - Other references / labels for png would need to be replaced

Miles

diff --git a/src/TileCache.zig b/src/TileCache.zig
index 17e662c..d8d0269 100644
--- a/src/TileCache.zig
+++ b/src/TileCache.zig
@@ -420,10 +420,11 @@ fn download_loop_transfer_complete(tile_cache: *@This(), msg: *curl.CURLMsg) !vo
                         sdl.SDL_RWFromConstMem(@ptrCast(&datum_array[0]), @intCast(datum_array.len)),
                     );
                     const is_valid_png_data = sdl.SDL_TRUE == sdl.IMG_isPNG(memory);
+                    const is_valid_jpg_data = sdl.SDL_TRUE == sdl.IMG_isJPG(memory);
                     try utilsdl.errorcheck(sdl.SDL_RWclose(memory));
 
                     // Save to FS
-                    if (is_valid_png_data) {
+                    if (is_valid_png_data or is_valid_jpg_data) {
                         const path = try png_path(tile_cache.allocator, p.get(p.pref.tile_cache_url).t.?, coords);
                         try cache_dir.writeFile(.{ .sub_path = path, .data = datum_array });
                     }
-- 
2.45.2