texture_set: streamed image loading

src/ggez/filesystem.rs

@@ -29,6 +29,7 @@
 use std::env;
 use std::fmt;
 use std::io;
+use std::io::SeekFrom;
 use std::path;
 
 use crate::ggez::{Context, GameError, GameResult};
@@ -87,6 +88,14 @@ impl io::Write for File {
     }
 }
 
+impl io::Seek for File {
+    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+        match *self {
+            File::VfsFile(ref mut f) => f.seek(pos),
+        }
+    }
+}
+
 impl Filesystem {
     /// Create a new `Filesystem` instance, using the given `id` and (on
     /// some platforms) the `author` as a portion of the user

src/ggez/vfs.rs

@@ -13,7 +13,7 @@
 use std::collections::VecDeque;
 use std::fmt::{self, Debug};
 use std::fs;
-use std::io::{Read, Seek, Write};
+use std::io::{Read, Seek, Write, BufRead};
 use std::path::{self, Path, PathBuf};
 
 use crate::ggez::error::{GameError, GameResult};

src/texture_set.rs

@@ -1,5 +1,5 @@
 use std::collections::HashMap;
-use std::io::Read;
+use std::io::{Read, BufReader, Seek, SeekFrom};
 
 use crate::ggez::{Context, GameError, GameResult};
 use crate::ggez::filesystem;
@@ -97,10 +97,12 @@ impl TextureSet {
 
     fn load_image(&self, ctx: &mut Context, path: &str) -> GameResult<Image> {
         let img = {
-            let mut buf = Vec::new();
+            let mut buf = [0u8; 8];
             let mut reader = filesystem::open(ctx, path)?;
-            let _ = reader.read_to_end(&mut buf)?;
+            reader.read_exact(&mut buf)?;
-            let image = image::load_from_memory(&buf)?;
+            reader.seek(SeekFrom::Start(0))?;
+
+            let image = image::load(BufReader::new(reader), image::guess_format(&buf)?)?;
             let mut rgba = image.to_rgba();
 
             if image.color().channel_count() != 4 {