Work on implementing interlacing [ci skip]

src/lib.rs

@@ -187,9 +187,6 @@ pub fn optimize(filepath: &Path, opts: &Options) -> Result<(), String> {
     if let Some(interlacing) = opts.interlace {
         if png.change_interlacing(interlacing) {
             something_changed = true;
-            if opts.verbosity == Some(1) {
-                report_reduction(&png);
-            }
         }
     }
 

src/png.rs

@@ -123,6 +123,8 @@ pub struct ScanLines<'a> {
     pub png: &'a PngData,
     start: usize,
     end: usize,
+    /// Current pass number, and 0-indexed row within the pass
+    pass: Option<(u8, u32)>,
 }
 
 impl<'a> Iterator for ScanLines<'a> {
@@ -130,7 +132,99 @@ impl<'a> Iterator for ScanLines<'a> {
     fn next(&mut self) -> Option<Self::Item> {
         if self.end == self.png.raw_data.len() {
             None
+        } else if self.png.ihdr_data.interlaced == 1 {
+            // Scanlines for interlaced PNG files
+            if self.pass.is_none() {
+                self.pass = Some((1, 0));
+            }
+            // Handle edge cases for images smaller than 5 pixels in either direction
+            if self.png.ihdr_data.width < 5 && self.pass.unwrap().0 == 2 {
+                if let Some(pass) = self.pass.as_mut() {
+                    pass.0 = 3;
+                    pass.1 = 4;
+                }
+            }
+            // Intentionally keep these separate so that they can be applied one after another
+            if self.png.ihdr_data.height < 5 && self.pass.unwrap().0 == 3 {
+                if let Some(pass) = self.pass.as_mut() {
+                    pass.0 = 4;
+                    pass.1 = 0;
+                }
+            }
+            let bits_per_pixel = self.png.ihdr_data.bit_depth.as_u8() as usize *
+                                 self.png.channels_per_pixel() as usize;
+            let mut bits_per_line = self.png.ihdr_data.width as usize * bits_per_pixel;
+            let y_steps;
+            match self.pass {
+                Some((1, _)) => {
+                    bits_per_line >>= 3;
+                    y_steps = 8;
+                }
+                Some((2, _)) => {
+                    bits_per_line >>= 3;
+                    y_steps = 8;
+                }
+                Some((3, _)) => {
+                    bits_per_line >>= 2;
+                    y_steps = 8;
+                }
+                Some((4, _)) => {
+                    bits_per_line >>= 2;
+                    y_steps = 4;
+                }
+                Some((5, _)) => {
+                    bits_per_line >>= 1;
+                    y_steps = 4;
+                }
+                Some((6, _)) => {
+                    bits_per_line >>= 1;
+                    y_steps = 2;
+                }
+                Some((7, _)) => {
+                    y_steps = 2;
+                }
+                _ => unreachable!(),
+            }
+            // Determine whether to trim the last (overflow) pixel for rows on this pass
+            let gap = bits_per_line % bits_per_pixel;
+            if gap != 0 {
+                let x_start = bits_per_pixel *
+                              match self.pass.unwrap().0 {
+                    2 => 4,
+                    4 => 2,
+                    6 => 1,
+                    _ => 0,
+                };
+                if gap >= x_start {
+                    bits_per_line += bits_per_pixel - gap;
+                } else {
+                    bits_per_line -= gap;
+                }
+            }
+            // Round up without converting to float
+            let bytes_per_line = (bits_per_line + bits_per_line % 8) >> 3;
+            self.start = self.end;
+            self.end = self.start + bytes_per_line + 1;
+            // TODO: Handle 4x4 pixel images
+            if let Some(pass) = self.pass.as_mut() {
+                if pass.1 + y_steps >= self.png.ihdr_data.height {
+                    pass.0 += 1;
+                    pass.1 = match pass.0 {
+                        3 => 4,
+                        5 => 2,
+                        7 => 1,
+                        _ => 0,
+                    };
+                } else {
+                    pass.1 += y_steps;
+                }
+            }
+            Some(ScanLine {
+                filter: self.png.raw_data[self.start],
+                data: self.png.raw_data[(self.start + 1)..self.end].to_owned(),
+            })
         } else {
+            // Standard, non-interlaced PNG scanlines
             let bits_per_line = self.png.ihdr_data.width as usize *
                                 self.png.ihdr_data.bit_depth.as_u8() as usize *
                                 self.png.channels_per_pixel() as usize;
@@ -338,6 +432,7 @@ impl PngData {
             png: &self,
             start: 0,
             end: 0,
+            pass: None,
         }
     }
     /// Reverse all filters applied on the image, returning an unfiltered IDAT bytestream
@@ -543,11 +638,15 @@ impl PngData {
     /// Convert the image to the specified interlacing type
     /// Returns true if the interlacing was changed, false otherwise
     pub fn change_interlacing(&mut self, interlace: u8) -> bool {
-        // TODO: Implement
-        if interlace != self.ihdr_data.interlaced {
+        if interlace == self.ihdr_data.interlaced {
             return false;
         }
 
+        if interlace == 1 {
+            // TODO: Interlace
+        } else {
+            // TODO: Deinterlace
+        }
         false
     }
 }

tests/files/generate.sh

@@ -0,0 +1,157 @@
+#/bin/bash
+cp rgba_16_should_be_rgba_16.png interlaced_rgba_16_should_be_rgba_16.png
+cp rgba_16_should_be_rgba_8.png interlaced_rgba_16_should_be_rgba_8.png
+cp rgba_8_should_be_rgba_8.png interlaced_rgba_8_should_be_rgba_8.png
+cp rgba_16_should_be_rgb_16.png interlaced_rgba_16_should_be_rgb_16.png
+cp rgba_16_should_be_rgb_8.png interlaced_rgba_16_should_be_rgb_8.png
+cp rgba_8_should_be_rgb_8.png interlaced_rgba_8_should_be_rgb_8.png
+cp rgba_16_should_be_palette_8.png interlaced_rgba_16_should_be_palette_8.png
+cp rgba_8_should_be_palette_8.png interlaced_rgba_8_should_be_palette_8.png
+cp rgba_16_should_be_palette_4.png interlaced_rgba_16_should_be_palette_4.png
+cp rgba_8_should_be_palette_4.png interlaced_rgba_8_should_be_palette_4.png
+cp rgba_16_should_be_palette_2.png interlaced_rgba_16_should_be_palette_2.png
+cp rgba_8_should_be_palette_2.png interlaced_rgba_8_should_be_palette_2.png
+cp rgba_16_should_be_palette_1.png interlaced_rgba_16_should_be_palette_1.png
+cp rgba_8_should_be_palette_1.png interlaced_rgba_8_should_be_palette_1.png
+cp rgba_16_should_be_grayscale_alpha_16.png interlaced_rgba_16_should_be_grayscale_alpha_16.png
+cp rgba_16_should_be_grayscale_alpha_8.png interlaced_rgba_16_should_be_grayscale_alpha_8.png
+cp rgba_8_should_be_grayscale_alpha_8.png interlaced_rgba_8_should_be_grayscale_alpha_8.png
+cp rgba_16_should_be_grayscale_16.png interlaced_rgba_16_should_be_grayscale_16.png
+cp rgba_16_should_be_grayscale_8.png interlaced_rgba_16_should_be_grayscale_8.png
+cp rgba_8_should_be_grayscale_8.png interlaced_rgba_8_should_be_grayscale_8.png
+cp rgba_16_should_be_palette_4_grayscale.png interlaced_rgba_16_should_be_palette_4_grayscale.png
+cp rgba_8_should_be_palette_4_grayscale.png interlaced_rgba_8_should_be_palette_4_grayscale.png
+cp rgba_16_should_be_palette_2_grayscale.png interlaced_rgba_16_should_be_palette_2_grayscale.png
+cp rgba_8_should_be_palette_2_grayscale.png interlaced_rgba_8_should_be_palette_2_grayscale.png
+cp rgba_16_should_be_palette_1_grayscale.png interlaced_rgba_16_should_be_palette_1_grayscale.png
+cp rgba_8_should_be_palette_1_grayscale.png interlaced_rgba_8_should_be_palette_1_grayscale.png
+cp rgb_16_should_be_rgb_16.png interlaced_rgb_16_should_be_rgb_16.png
+cp rgb_16_should_be_rgb_8.png interlaced_rgb_16_should_be_rgb_8.png
+cp rgb_8_should_be_rgb_8.png interlaced_rgb_8_should_be_rgb_8.png
+cp rgb_16_should_be_palette_8.png interlaced_rgb_16_should_be_palette_8.png
+cp rgb_8_should_be_palette_8.png interlaced_rgb_8_should_be_palette_8.png
+cp rgb_16_should_be_palette_4.png interlaced_rgb_16_should_be_palette_4.png
+cp rgb_8_should_be_palette_4.png interlaced_rgb_8_should_be_palette_4.png
+cp rgb_16_should_be_palette_2.png interlaced_rgb_16_should_be_palette_2.png
+cp rgb_8_should_be_palette_2.png interlaced_rgb_8_should_be_palette_2.png
+cp rgb_16_should_be_palette_1.png interlaced_rgb_16_should_be_palette_1.png
+cp rgb_8_should_be_palette_1.png interlaced_rgb_8_should_be_palette_1.png
+cp rgb_16_should_be_grayscale_16.png interlaced_rgb_16_should_be_grayscale_16.png
+cp rgb_16_should_be_grayscale_8.png interlaced_rgb_16_should_be_grayscale_8.png
+cp rgb_8_should_be_grayscale_8.png interlaced_rgb_8_should_be_grayscale_8.png
+cp rgb_16_should_be_palette_4_grayscale.png interlaced_rgb_16_should_be_palette_4_grayscale.png
+cp rgb_8_should_be_palette_4_grayscale.png interlaced_rgb_8_should_be_palette_4_grayscale.png
+cp rgb_16_should_be_palette_2_grayscale.png interlaced_rgb_16_should_be_palette_2_grayscale.png
+cp rgb_8_should_be_palette_2_grayscale.png interlaced_rgb_8_should_be_palette_2_grayscale.png
+cp rgb_16_should_be_palette_1_grayscale.png interlaced_rgb_16_should_be_palette_1_grayscale.png
+cp rgb_8_should_be_palette_1_grayscale.png interlaced_rgb_8_should_be_palette_1_grayscale.png
+cp palette_8_should_be_grayscale_8.png interlaced_palette_8_should_be_grayscale_8.png
+cp palette_8_should_be_palette_8.png interlaced_palette_8_should_be_palette_8.png
+cp palette_8_should_be_palette_4.png interlaced_palette_8_should_be_palette_4.png
+cp palette_4_should_be_palette_4.png interlaced_palette_4_should_be_palette_4.png
+cp palette_8_should_be_palette_2.png interlaced_palette_8_should_be_palette_2.png
+cp palette_4_should_be_palette_2.png interlaced_palette_4_should_be_palette_2.png
+cp palette_2_should_be_palette_2.png interlaced_palette_2_should_be_palette_2.png
+cp palette_8_should_be_palette_1.png interlaced_palette_8_should_be_palette_1.png
+cp palette_4_should_be_palette_1.png interlaced_palette_4_should_be_palette_1.png
+cp palette_2_should_be_palette_1.png interlaced_palette_2_should_be_palette_1.png
+cp palette_1_should_be_palette_1.png interlaced_palette_1_should_be_palette_1.png
+cp grayscale_alpha_16_should_be_grayscale_alpha_16.png interlaced_grayscale_alpha_16_should_be_grayscale_alpha_16.png
+cp grayscale_alpha_16_should_be_grayscale_alpha_8.png interlaced_grayscale_alpha_16_should_be_grayscale_alpha_8.png
+cp grayscale_alpha_8_should_be_grayscale_alpha_8.png interlaced_grayscale_alpha_8_should_be_grayscale_alpha_8.png
+cp grayscale_alpha_16_should_be_grayscale_16.png interlaced_grayscale_alpha_16_should_be_grayscale_16.png
+cp grayscale_alpha_16_should_be_grayscale_8.png interlaced_grayscale_alpha_16_should_be_grayscale_8.png
+cp grayscale_alpha_8_should_be_grayscale_8.png interlaced_grayscale_alpha_8_should_be_grayscale_8.png
+cp grayscale_alpha_16_should_be_palette_4.png interlaced_grayscale_alpha_16_should_be_palette_4.png
+cp grayscale_alpha_8_should_be_palette_4.png interlaced_grayscale_alpha_8_should_be_palette_4.png
+cp grayscale_alpha_16_should_be_palette_2.png interlaced_grayscale_alpha_16_should_be_palette_2.png
+cp grayscale_alpha_8_should_be_palette_2.png interlaced_grayscale_alpha_8_should_be_palette_2.png
+cp grayscale_alpha_16_should_be_palette_1.png interlaced_grayscale_alpha_16_should_be_palette_1.png
+cp grayscale_alpha_8_should_be_palette_1.png interlaced_grayscale_alpha_8_should_be_palette_1.png
+cp grayscale_16_should_be_grayscale_16.png interlaced_grayscale_16_should_be_grayscale_16.png
+cp grayscale_16_should_be_grayscale_8.png interlaced_grayscale_16_should_be_grayscale_8.png
+cp grayscale_16_should_be_palette_4.png interlaced_grayscale_16_should_be_palette_4.png
+cp grayscale_16_should_be_palette_2.png interlaced_grayscale_16_should_be_palette_2.png
+cp grayscale_16_should_be_palette_1.png interlaced_grayscale_16_should_be_palette_1.png
+cp grayscale_8_should_be_grayscale_8.png interlaced_grayscale_8_should_be_grayscale_8.png
+cp grayscale_8_should_be_palette_4.png interlaced_grayscale_8_should_be_palette_4.png
+cp grayscale_8_should_be_palette_2.png interlaced_grayscale_8_should_be_palette_2.png
+cp grayscale_8_should_be_palette_1.png interlaced_grayscale_8_should_be_palette_1.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_rgba_16.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_rgba_8.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_rgba_8.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_rgb_16.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_rgb_8.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_rgb_8.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_8.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_8.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_4.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_4.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_2.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_2.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_1.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_1.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_grayscale_alpha_16.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_grayscale_alpha_8.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_grayscale_alpha_8.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_grayscale_16.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_4_grayscale.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_4_grayscale.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_2_grayscale.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_2_grayscale.png
+optipng -nx -i 1 interlaced_rgba_16_should_be_palette_1_grayscale.png
+optipng -nx -i 1 interlaced_rgba_8_should_be_palette_1_grayscale.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_rgb_16.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_rgb_8.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_rgb_8.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_8.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_8.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_4.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_4.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_2.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_2.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_1.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_1.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_grayscale_16.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_4_grayscale.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_4_grayscale.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_2_grayscale.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_2_grayscale.png
+optipng -nx -i 1 interlaced_rgb_16_should_be_palette_1_grayscale.png
+optipng -nx -i 1 interlaced_rgb_8_should_be_palette_1_grayscale.png
+optipng -nx -i 1 interlaced_palette_8_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_palette_8_should_be_palette_8.png
+optipng -nx -i 1 interlaced_palette_8_should_be_palette_4.png
+optipng -nx -i 1 interlaced_palette_4_should_be_palette_4.png
+optipng -nx -i 1 interlaced_palette_8_should_be_palette_2.png
+optipng -nx -i 1 interlaced_palette_4_should_be_palette_2.png
+optipng -nx -i 1 interlaced_palette_2_should_be_palette_2.png
+optipng -nx -i 1 interlaced_palette_8_should_be_palette_1.png
+optipng -nx -i 1 interlaced_palette_4_should_be_palette_1.png
+optipng -nx -i 1 interlaced_palette_2_should_be_palette_1.png
+optipng -nx -i 1 interlaced_palette_1_should_be_palette_1.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_grayscale_alpha_16.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_grayscale_alpha_8.png
+optipng -nx -i 1 interlaced_grayscale_alpha_8_should_be_grayscale_alpha_8.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_grayscale_16.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_grayscale_alpha_8_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_palette_4.png
+optipng -nx -i 1 interlaced_grayscale_alpha_8_should_be_palette_4.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_palette_2.png
+optipng -nx -i 1 interlaced_grayscale_alpha_8_should_be_palette_2.png
+optipng -nx -i 1 interlaced_grayscale_alpha_16_should_be_palette_1.png
+optipng -nx -i 1 interlaced_grayscale_alpha_8_should_be_palette_1.png
+optipng -nx -i 1 interlaced_grayscale_16_should_be_grayscale_16.png
+optipng -nx -i 1 interlaced_grayscale_16_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_grayscale_16_should_be_palette_4.png
+optipng -nx -i 1 interlaced_grayscale_16_should_be_palette_2.png
+optipng -nx -i 1 interlaced_grayscale_16_should_be_palette_1.png
+optipng -nx -i 1 interlaced_grayscale_8_should_be_grayscale_8.png
+optipng -nx -i 1 interlaced_grayscale_8_should_be_palette_4.png
+optipng -nx -i 1 interlaced_grayscale_8_should_be_palette_2.png
+optipng -nx -i 1 interlaced_grayscale_8_should_be_palette_1.png

tests/flags.rs

@@ -267,3 +267,77 @@ fn strip_headers_none() {
 
     remove_file(output).ok();
 }
+
+#[test]
+fn interlacing_0_to_1() {
+    let input = PathBuf::from("tests/files/interlacing_0_to_1.png");
+    let mut opts = get_opts(&input);
+    opts.interlace = Some(1);
+    let output = opts.out_file.clone();
+
+    let png = png::PngData::new(&input).unwrap();
+
+    assert!(png.ihdr_data.interlaced == 0);
+
+    match oxipng::optimize(&input, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!(x.to_owned()),
+    };
+    assert!(output.exists());
+
+    let png = match png::PngData::new(&output) {
+        Ok(x) => x,
+        Err(x) => {
+            remove_file(output).ok();
+            panic!(x.to_owned())
+        }
+    };
+
+    assert!(png.ihdr_data.interlaced == 1);
+
+    let old_png = image::open(&input).unwrap();
+    let new_png = image::open(&output).unwrap();
+
+    // Conversion should be lossless
+    assert!(old_png.pixels().map(|x| x.2.channels().to_owned()).collect::<Vec<Vec<u8>>>() ==
+            new_png.pixels().map(|x| x.2.channels().to_owned()).collect::<Vec<Vec<u8>>>());
+
+    remove_file(output).ok();
+}
+
+#[test]
+fn interlacing_1_to_0() {
+    let input = PathBuf::from("tests/files/interlacing_1_to_0.png");
+    let mut opts = get_opts(&input);
+    opts.interlace = Some(0);
+    let output = opts.out_file.clone();
+
+    let png = png::PngData::new(&input).unwrap();
+
+    assert!(png.ihdr_data.interlaced == 1);
+
+    match oxipng::optimize(&input, &opts) {
+        Ok(_) => (),
+        Err(x) => panic!(x.to_owned()),
+    };
+    assert!(output.exists());
+
+    let png = match png::PngData::new(&output) {
+        Ok(x) => x,
+        Err(x) => {
+            remove_file(output).ok();
+            panic!(x.to_owned())
+        }
+    };
+
+    assert!(png.ihdr_data.interlaced == 0);
+
+    let old_png = image::open(&input).unwrap();
+    let new_png = image::open(&output).unwrap();
+
+    // Conversion should be lossless
+    assert!(old_png.pixels().map(|x| x.2.channels().to_owned()).collect::<Vec<Vec<u8>>>() ==
+            new_png.pixels().map(|x| x.2.channels().to_owned()).collect::<Vec<Vec<u8>>>());
+
+    remove_file(output).ok();
+}

tests/reduction.rs

@@ -60,6 +60,7 @@ fn test_it_converts(input: &Path,
 
     assert!(png.ihdr_data.color_type == color_type_in);
     assert!(png.ihdr_data.bit_depth == bit_depth_in);
+    assert!(png.ihdr_data.interlaced == 0);
 
     match oxipng::optimize(input, opts) {
         Ok(_) => (),