Add alpha filter tests

tests/alpha.rs

@@ -0,0 +1,346 @@
+use std::{
+    fs::remove_file,
+    path::{Path, PathBuf},
+};
+
+use oxipng::{internal_tests::*, *};
+
+const GRAYSCALE_ALPHA: u8 = 4;
+const RGBA: u8 = 6;
+
+fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
+    let options = oxipng::Options {
+        force: true,
+        optimize_alpha: true,
+        ..Default::default()
+    };
+    (OutFile::from_path(input.with_extension("out.png")), options)
+}
+
+fn test_it_converts(
+    input: &str,
+    filter: FilterStrategy,
+    color_type_in: u8,
+    bit_depth_in: BitDepth,
+    color_type_out: u8,
+    bit_depth_out: BitDepth,
+) {
+    let input = PathBuf::from(input);
+
+    let (output, mut opts) = get_opts(&input);
+    let png = PngData::new(&input, &opts).unwrap();
+    opts.filters = indexset! {filter};
+    assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_in);
+    assert_eq!(png.raw.ihdr.bit_depth, bit_depth_in);
+
+    match oxipng::optimize(&InFile::Path(input), &output, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!("{}", x),
+    };
+    let output = output.path().unwrap();
+    assert!(output.exists());
+
+    let png = match PngData::new(output, &opts) {
+        Ok(x) => x,
+        Err(x) => {
+            remove_file(output).ok();
+            panic!("{}", x)
+        }
+    };
+
+    assert_eq!(png.raw.ihdr.color_type.png_header_code(), color_type_out);
+    assert_eq!(png.raw.ihdr.bit_depth, bit_depth_out);
+    if let ColorType::Indexed { palette } = &png.raw.ihdr.color_type {
+        assert!(palette.len() <= 1 << (png.raw.ihdr.bit_depth as u8));
+    }
+
+    remove_file(output).ok();
+}
+
+#[test]
+fn alpha_filter_0_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_0_for_rgba_16.png",
+        FilterStrategy::NONE,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_1_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_1_for_rgba_16.png",
+        FilterStrategy::SUB,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_2_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_2_for_rgba_16.png",
+        FilterStrategy::UP,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_3_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_3_for_rgba_16.png",
+        FilterStrategy::AVERAGE,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_4_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_4_for_rgba_16.png",
+        FilterStrategy::PAETH,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_5_for_rgba_16() {
+    test_it_converts(
+        "tests/files/filter_5_for_rgba_16.png",
+        FilterStrategy::MinSum,
+        RGBA,
+        BitDepth::Sixteen,
+        RGBA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_0_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_0_for_rgba_8.png",
+        FilterStrategy::NONE,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_1_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_1_for_rgba_8.png",
+        FilterStrategy::SUB,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_2_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_2_for_rgba_8.png",
+        FilterStrategy::UP,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_3_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_3_for_rgba_8.png",
+        FilterStrategy::AVERAGE,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_4_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_4_for_rgba_8.png",
+        FilterStrategy::PAETH,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_5_for_rgba_8() {
+    test_it_converts(
+        "tests/files/filter_5_for_rgba_8.png",
+        FilterStrategy::MinSum,
+        RGBA,
+        BitDepth::Eight,
+        RGBA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_0_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_0_for_grayscale_alpha_16.png",
+        FilterStrategy::NONE,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_1_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_1_for_grayscale_alpha_16.png",
+        FilterStrategy::SUB,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_2_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_2_for_grayscale_alpha_16.png",
+        FilterStrategy::UP,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_3_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_3_for_grayscale_alpha_16.png",
+        FilterStrategy::AVERAGE,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_4_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_4_for_grayscale_alpha_16.png",
+        FilterStrategy::PAETH,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_5_for_grayscale_alpha_16() {
+    test_it_converts(
+        "tests/files/filter_5_for_grayscale_alpha_16.png",
+        FilterStrategy::MinSum,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+        GRAYSCALE_ALPHA,
+        BitDepth::Sixteen,
+    );
+}
+
+#[test]
+fn alpha_filter_0_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_0_for_grayscale_alpha_8.png",
+        FilterStrategy::NONE,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_1_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_1_for_grayscale_alpha_8.png",
+        FilterStrategy::SUB,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_2_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_2_for_grayscale_alpha_8.png",
+        FilterStrategy::UP,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_3_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_3_for_grayscale_alpha_8.png",
+        FilterStrategy::AVERAGE,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_4_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_4_for_grayscale_alpha_8.png",
+        FilterStrategy::PAETH,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}
+
+#[test]
+fn alpha_filter_5_for_grayscale_alpha_8() {
+    test_it_converts(
+        "tests/files/filter_5_for_grayscale_alpha_8.png",
+        FilterStrategy::MinSum,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+        GRAYSCALE_ALPHA,
+        BitDepth::Eight,
+    );
+}