Merge branch 'wip/sophie-h/workspace' into 'main'

meta: Move lib and bins into separate crates

Closes #950

See merge request GNOME/librsvg!822

1 files changed, 112 insertions, 0 deletions

diff --git a/rsvg/src/test_utils/compare_surfaces.rs b/rsvg/src/test_utils/compare_surfaces.rs
new file mode 100644
index 00000000..06100db9
--- /dev/null
+++ b/rsvg/src/test_utils/compare_surfaces.rs
@@ -0,0 +1,112 @@
+use std::fmt;
+
+use crate::surface_utils::{
+    iterators::Pixels,
+    shared_surface::{SharedImageSurface, SurfaceType},
+    ImageSurfaceDataExt, Pixel, PixelOps,
+};
+
+use rgb::{ComponentMap, RGB};
+
+pub enum BufferDiff {
+    DifferentSizes,
+    Diff(Diff),
+}
+
+pub struct Diff {
+    pub num_pixels_changed: usize,
+    pub max_diff: u8,
+    pub surface: SharedImageSurface,
+}
+
+impl fmt::Display for BufferDiff {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            BufferDiff::DifferentSizes => write!(f, "different sizes"),
+            BufferDiff::Diff(diff) => diff.fmt(f),
+        }
+    }
+}
+
+impl fmt::Display for Diff {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(
+            f,
+            "{} pixels are different, with a maximum difference of {}",
+            self.num_pixels_changed, self.max_diff
+        )
+    }
+}
+
+#[inline]
+fn emphasize(p: &Pixel) -> Pixel {
+    let emphasize_component = |c| {
+        // emphasize
+        let mut c = c as u32 * 4;
+        // make sure it's visible
+        if c > 0 {
+            c += 128;
+        }
+        c.min(255) as u8
+    };
+    p.map(emphasize_component)
+}
+
+pub fn compare_surfaces(
+    surf_a: &SharedImageSurface,
+    surf_b: &SharedImageSurface,
+) -> Result<BufferDiff, cairo::Error> {
+    let a_width = surf_a.width();
+    let a_height = surf_a.height();
+
+    let b_width = surf_b.width();
+    let b_height = surf_b.height();
+
+    if a_width != b_width || a_height != b_height {
+        return Ok(BufferDiff::DifferentSizes);
+    }
+
+    let mut surf_diff = cairo::ImageSurface::create(cairo::Format::ARgb32, a_width, a_height)?;
+    let diff_stride = surf_diff.stride() as usize;
+
+    let mut num_pixels_changed = 0;
+    let mut max_diff = 0;
+
+    let black = Pixel::default().alpha(255);
+
+    {
+        let mut diff_data = surf_diff.data().unwrap();
+
+        for ((xa, ya, pixel_a), (_, _, pixel_b)) in Pixels::new(surf_a).zip(Pixels::new(surf_b)) {
+            let dest = if pixel_a != pixel_b {
+                num_pixels_changed += 1;
+
+                let pixel_diff = pixel_a.diff(&pixel_b);
+
+                max_diff = pixel_diff.iter().fold(max_diff, |acc, c| acc.max(c));
+
+                let pixel_diff = emphasize(&pixel_diff);
+
+                if pixel_diff.rgb() == RGB::default() {
+                    // alpha only difference; convert alpha to gray
+                    let a = pixel_diff.a;
+                    pixel_diff.map_rgb(|_| a)
+                } else {
+                    pixel_diff.alpha(255)
+                }
+            } else {
+                black
+            };
+
+            diff_data.set_pixel(diff_stride, dest, xa, ya);
+        }
+    }
+
+    let surface = SharedImageSurface::wrap(surf_diff, SurfaceType::SRgb)?;
+
+    Ok(BufferDiff::Diff(Diff {
+        num_pixels_changed,
+        max_diff,
+        surface,
+    }))
+}