1 files changed, 103 insertions, 0 deletions
diff --git a/vendor/gif/tests/roundtrip.rs b/vendor/gif/tests/roundtrip.rs
new file mode 100644
index 0000000..c121508
--- /dev/null
+++ b/vendor/gif/tests/roundtrip.rs
@@ -0,0 +1,103 @@
+use gif::{ColorOutput, Decoder, Encoder, Frame};
+
+#[test]
+fn encode_roundtrip() {
+    const ORIGINAL: &'static [u8] = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/tests/samples/2x2.gif"));
+    round_trip_from_image(ORIGINAL);
+}
+
+fn round_trip_from_image(original: &[u8]) {
+    let (width, height, global_palette);
+    let frames: Vec<Frame> = {
+        let mut decoder = Decoder::new(original).unwrap();
+        width = decoder.width();
+        height = decoder.height();
+        global_palette = decoder
+            .global_palette()
+            .unwrap_or_default()
+            .to_vec();
+        core::iter::from_fn(move || {
+            decoder.read_next_frame().unwrap().cloned()
+        }).collect()
+    };
+
+    let mut encoder = Encoder::new(vec![], width, height, &global_palette).unwrap();
+    for frame in &frames {
+        encoder.write_frame(frame).unwrap();
+    }
+    let buffer = encoder.into_inner().unwrap();
+
+    {
+        let mut decoder = Decoder::new(&buffer[..]).expect("Invalid info encoded");
+        assert_eq!(decoder.width(), width);
+        assert_eq!(decoder.height(), height);
+        assert_eq!(global_palette, decoder.global_palette().unwrap_or_default());
+        let new_frames: Vec<_> = core::iter::from_fn(move || {
+            decoder.read_next_frame().unwrap().cloned()
+        }).collect();
+        assert_eq!(new_frames.len(), frames.len(), "Diverging number of frames");
+        for (new, reference) in new_frames.iter().zip(&frames) {
+            assert_eq!(new.delay, reference.delay);
+            assert_eq!(new.dispose, reference.dispose);
+            assert_eq!(new.transparent, reference.transparent);
+            assert_eq!(new.needs_user_input, reference.needs_user_input);
+            assert_eq!(new.top, reference.top);
+            assert_eq!(new.left, reference.left);
+            assert_eq!(new.width, reference.width);
+            assert_eq!(new.height, reference.height);
+            assert_eq!(new.interlaced, reference.interlaced);
+            assert_eq!(new.palette, reference.palette);
+            assert_eq!(new.buffer, reference.buffer);
+        }
+    }
+}
+
+#[test]
+#[cfg(feature = "color_quant")]
+fn encode_roundtrip_few_colors() {
+    const WIDTH: u16 = 128;
+    const HEIGHT: u16 = 128;
+
+    // Build an image with a single red pixel, that NeuQuant won't
+    // sample, in order to check that we do appropriatelyq specialise the
+    // few-colors case.
+    let mut pixels: Vec<u8> = vec![255; WIDTH as usize * HEIGHT as usize * 4];
+    // Top-left pixel is always sampled, so use the second pixel.
+    pixels[5] = 0;
+    pixels[6] = 0;
+    // Set speed to 30 to handily avoid sampling that one pixel.
+    //
+    // We clone "pixels", since the parameter is replaced with a
+    // paletted version, and later we want to compare the output with
+    // the original RGBA image.
+    let mut frame = Frame::from_rgba_speed(WIDTH, HEIGHT, &mut pixels.clone(), 30);
+
+    let mut buffer = vec![];
+    {
+        let mut encoder = Encoder::new(&mut buffer, WIDTH, HEIGHT, &[]).unwrap();
+        encoder.write_frame(&frame).unwrap();
+
+        frame.make_lzw_pre_encoded();
+        encoder.write_lzw_pre_encoded_frame(&frame).unwrap();
+    }
+
+    {
+        let mut decoder = {
+            let mut builder = Decoder::<&[u8]>::build();
+            builder.set_color_output(ColorOutput::RGBA);
+            builder.read_info(&buffer[..]).expect("Invalid info encoded")
+        };
+
+        // Only check key fields, assuming "round_trip_from_image"
+        // covers the rest. We are primarily concerned with quantisation.
+        assert_eq!(decoder.width(), WIDTH);
+        assert_eq!(decoder.height(), HEIGHT);
+        let new_frames: Vec<_> = core::iter::from_fn(move || {
+            decoder.read_next_frame().unwrap().cloned()
+        }).collect();
+        assert_eq!(new_frames.len(), 2, "Diverging number of frames");
+        // NB: reference.buffer can't be used as it contains the palette version.
+        assert_eq!(new_frames[0].buffer, pixels);
+        assert_eq!(new_frames[1].buffer, pixels);
+    }
+}