Struct Mask

pub struct Mask { /* private fields */ }

A mask.

During drawing over Pixmap, mask’s black (0) “pixels” would block rendering and white (255) will allow it. Anything in between is used for gradual masking and anti-aliasing.

Unlike Skia, we’re using just a simple 8bit alpha mask. It’s way slower, but easier to implement.

Implementations

impl Mask

pub fn new(width: u32, height: u32) -> Option<Self>

Creates a new mask by taking ownership over a mask buffer.

The size needs to match the data provided.

Examples found in repository

examples/mask.rs (line 15)

fn main() {
    let clip_path = {
        let mut pb = PathBuilder::new();
        pb.push_circle(250.0, 250.0, 200.0);
        pb.push_circle(250.0, 250.0, 100.0);
        pb.finish().unwrap()
    };

    let clip_path = clip_path
        .transform(Transform::from_row(1.0, -0.3, 0.0, 1.0, 0.0, 75.0))
        .unwrap();

    let mut mask = Mask::new(500, 500).unwrap();
    mask.fill_path(&clip_path, FillRule::EvenOdd, true, Transform::default());

    let mut paint = Paint::default();
    paint.anti_alias = false;
    paint.set_color_rgba8(50, 127, 150, 200);

    let mut pixmap = Pixmap::new(500, 500).unwrap();
    pixmap.fill_rect(
        Rect::from_xywh(0.0, 0.0, 500.0, 500.0).unwrap(),
        &paint,
        Transform::identity(),
        Some(&mask),
    );
    pixmap.save_png("image.png").unwrap();
}

examples/large_image.rs (line 35)

fn main() {
    let path1 = {
        let mut pb = PathBuilder::new();
        pb.move_to(1200.0, 1200.0);
        pb.line_to(3200.0, 18800.0);
        pb.cubic_to(7600.0, 16800.0, 13200.0, 16000.0, 18800.0, 16000.0);
        pb.cubic_to(14800.0, 9200.0, 8800.0, 3200.0, 1200.0, 1200.0);
        pb.close();
        pb.finish().unwrap()
    };

    let path2 = {
        let mut pb = PathBuilder::new();
        pb.move_to(18800.0, 1200.0);
        pb.line_to(16800.0, 18800.0);
        pb.cubic_to(12400.0, 16800.0, 6800.0, 16000.0, 1200.0, 16000.0);
        pb.cubic_to(5200.0, 9200.0, 11200.0, 3200.0, 18800.0, 1200.0);
        pb.close();
        pb.finish().unwrap()
    };

    let mut pixmap = Pixmap::new(20000, 20000).unwrap();

    let clip_path = {
        let mut pb = PathBuilder::new();
        pb.push_circle(10000.0, 10000.0, 7000.0);
        pb.finish().unwrap()
    };

    let mut mask = Mask::new(20000, 20000).unwrap();
    mask.fill_path(&clip_path, FillRule::Winding, true, Transform::default());

    let mut paint = Paint::default();
    paint.set_color_rgba8(90, 175, 100, 150);
    paint.anti_alias = true;
    let large_rect = Rect::from_xywh(500.0, 500.0, 19000.0, 19000.0).unwrap();
    pixmap.fill_rect(large_rect, &paint, Transform::identity(), None);

    paint.set_color_rgba8(50, 127, 150, 200);
    paint.anti_alias = true;
    pixmap.fill_path(
        &path1,
        &paint,
        FillRule::Winding,
        Transform::default(),
        Some(&mask),
    );

    paint.set_color_rgba8(220, 140, 75, 180);
    paint.anti_alias = false;
    pixmap.fill_path(
        &path2,
        &paint,
        FillRule::Winding,
        Transform::default(),
        None,
    );

    paint.set_color_rgba8(255, 10, 15, 180);
    paint.anti_alias = true;
    let mut stroke = Stroke::default();
    stroke.width = 0.8; // hairline
    pixmap.stroke_path(&path2, &paint, &stroke, Transform::default(), None);

    pixmap.save_png("image.png").unwrap();
}

pub fn from_pixmap(pixmap: PixmapRef<'_>, mask_type: MaskType) -> Self

Creates a new mask from a PixmapRef.

pub fn from_vec(data: Vec<u8>, size: IntSize) -> Option<Self>

Creates a new mask by taking ownership over a mask buffer.

The size needs to match the data provided.

pub fn width(&self) -> u32

Returns mask’s width.

pub fn height(&self) -> u32

Returns mask’s height.

pub fn data(&self) -> &[u8]

Returns the internal data.

pub fn data_mut(&mut self) -> &mut [u8]

Returns the mutable internal data.

pub fn decode_png(data: &[u8]) -> Result<Self, DecodingError>

Loads a PNG file into a Mask.

Only grayscale images are supported.

pub fn load_png<P: AsRef<Path>>(path: P) -> Result<Self, DecodingError>

Loads a PNG file into a Mask.

Only grayscale images are supported.

pub fn encode_png(&self) -> Result<Vec<u8>, EncodingError>

Encodes mask into a PNG data.

pub fn save_png<P: AsRef<Path>>(&self, path: P) -> Result<(), EncodingError>

Saves mask as a PNG file.

pub fn fill_path( &mut self, path: &Path, fill_rule: FillRule, anti_alias: bool, transform: Transform, )

Draws a filled path onto the mask.

In terms of RGB (no alpha) image, draws a white path on top of black mask.

Doesn’t reset the existing mask content and draws the path on top of existing data.

If the above behavior is undesired, Mask::clear() should be called first.

This method is intended to be used for simple cases. For more complex masks prefer Mask::from_pixmap().

Examples found in repository

examples/mask.rs (line 16)

fn main() {
    let clip_path = {
        let mut pb = PathBuilder::new();
        pb.push_circle(250.0, 250.0, 200.0);
        pb.push_circle(250.0, 250.0, 100.0);
        pb.finish().unwrap()
    };

    let clip_path = clip_path
        .transform(Transform::from_row(1.0, -0.3, 0.0, 1.0, 0.0, 75.0))
        .unwrap();

    let mut mask = Mask::new(500, 500).unwrap();
    mask.fill_path(&clip_path, FillRule::EvenOdd, true, Transform::default());

    let mut paint = Paint::default();
    paint.anti_alias = false;
    paint.set_color_rgba8(50, 127, 150, 200);

    let mut pixmap = Pixmap::new(500, 500).unwrap();
    pixmap.fill_rect(
        Rect::from_xywh(0.0, 0.0, 500.0, 500.0).unwrap(),
        &paint,
        Transform::identity(),
        Some(&mask),
    );
    pixmap.save_png("image.png").unwrap();
}

examples/large_image.rs (line 36)

fn main() {
    let path1 = {
        let mut pb = PathBuilder::new();
        pb.move_to(1200.0, 1200.0);
        pb.line_to(3200.0, 18800.0);
        pb.cubic_to(7600.0, 16800.0, 13200.0, 16000.0, 18800.0, 16000.0);
        pb.cubic_to(14800.0, 9200.0, 8800.0, 3200.0, 1200.0, 1200.0);
        pb.close();
        pb.finish().unwrap()
    };

    let path2 = {
        let mut pb = PathBuilder::new();
        pb.move_to(18800.0, 1200.0);
        pb.line_to(16800.0, 18800.0);
        pb.cubic_to(12400.0, 16800.0, 6800.0, 16000.0, 1200.0, 16000.0);
        pb.cubic_to(5200.0, 9200.0, 11200.0, 3200.0, 18800.0, 1200.0);
        pb.close();
        pb.finish().unwrap()
    };

    let mut pixmap = Pixmap::new(20000, 20000).unwrap();

    let clip_path = {
        let mut pb = PathBuilder::new();
        pb.push_circle(10000.0, 10000.0, 7000.0);
        pb.finish().unwrap()
    };

    let mut mask = Mask::new(20000, 20000).unwrap();
    mask.fill_path(&clip_path, FillRule::Winding, true, Transform::default());

    let mut paint = Paint::default();
    paint.set_color_rgba8(90, 175, 100, 150);
    paint.anti_alias = true;
    let large_rect = Rect::from_xywh(500.0, 500.0, 19000.0, 19000.0).unwrap();
    pixmap.fill_rect(large_rect, &paint, Transform::identity(), None);

    paint.set_color_rgba8(50, 127, 150, 200);
    paint.anti_alias = true;
    pixmap.fill_path(
        &path1,
        &paint,
        FillRule::Winding,
        Transform::default(),
        Some(&mask),
    );

    paint.set_color_rgba8(220, 140, 75, 180);
    paint.anti_alias = false;
    pixmap.fill_path(
        &path2,
        &paint,
        FillRule::Winding,
        Transform::default(),
        None,
    );

    paint.set_color_rgba8(255, 10, 15, 180);
    paint.anti_alias = true;
    let mut stroke = Stroke::default();
    stroke.width = 0.8; // hairline
    pixmap.stroke_path(&path2, &paint, &stroke, Transform::default(), None);

    pixmap.save_png("image.png").unwrap();
}

pub fn intersect_path( &mut self, path: &Path, fill_rule: FillRule, anti_alias: bool, transform: Transform, )

Intersects the provided path with the current clipping path.

A temporary mask with the same size as the current one will be created.

pub fn invert(&mut self)

Inverts the mask.

pub fn clear(&mut self)

Clears the mask.

Zero-fills the internal data buffer.

Trait Implementations

impl Clone for Mask

fn clone(&self) -> Mask

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Mask

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for Mask

fn eq(&self, other: &Mask) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Mask