core: Implements `BitmapData.pixelDissolve()` for AVM2.

The changes have automated tests for them.

The implementation has not been implemented or tested for AVM1 yet.

core/src/avm2/globals/flash/display/BitmapData.as

@@ -61,6 +61,10 @@ package flash.display {
             sourceBitmapData:BitmapData, sourceRect:Rectangle, destPoint:Point, operation:String, threshold:uint, color:uint = 0, mask:uint = 0xFFFFFFFF, copySource:Boolean = false
         ):uint;
         public native function compare(otherBitmapData:BitmapData):Object;
+        public native function pixelDissolve(
+            sourceBitmapData:BitmapData, sourceRect:Rectangle, destPoint:Point, randomSeed:int = 0, numPixels:int = 0,
+            fillColor:uint = 0
+        ):int;
 
         public function generateFilterRect(sourceRect:Rectangle, filter:BitmapFilter):Rectangle {
             stub_method("flash.display.BitmapData", "generateFilterRect");

core/src/avm2/globals/flash/display/bitmap_data.rs

@@ -1,7 +1,7 @@
 //! `flash.display.BitmapData` builtin/prototype
 
 use crate::avm2::activation::Activation;
-use crate::avm2::error::{argument_error, make_error_2008};
+use crate::avm2::error::{argument_error, make_error_2008, range_error};
 use crate::avm2::filters::FilterAvm2Ext;
 use crate::avm2::object::{BitmapDataObject, ByteArrayObject, Object, TObject, VectorObject};
 use crate::avm2::value::Value;
@@ -1050,7 +1050,7 @@ pub fn apply_filter<'gc>(
             source_rect.width().to_pixels().ceil() as u32,
             source_rect.height().to_pixels().ceil() as u32,
         );
-        let dest_point = args.get_object(activation, 2, "dstPoint")?;
+        let dest_point = args.get_object(activation, 2, "destPoint")?;
         let dest_point = (
             dest_point
                 .get_public_property("x", activation)?
@@ -1123,7 +1123,7 @@ pub fn palette_map<'gc>(
             source_rect.width().to_pixels().ceil() as i32,
             source_rect.height().to_pixels().ceil() as i32,
         );
-        let dest_point = args.get_object(activation, 2, "dstPoint")?;
+        let dest_point = args.get_object(activation, 2, "destPoint")?;
         let dest_point = (
             dest_point
                 .get_public_property("x", activation)?
@@ -1239,7 +1239,7 @@ pub fn threshold<'gc>(
         if !bitmap_data.disposed() {
             let src_bitmap = args.get_object(activation, 0, "sourceBitmapData")?;
             let source_rect = args.get_object(activation, 1, "sourceRect")?;
-            let dest_point = args.get_object(activation, 2, "dstPoint")?;
+            let dest_point = args.get_object(activation, 2, "destPoint")?;
             let dest_point = (
                 dest_point
                     .get_public_property("x", activation)?
@@ -1336,11 +1336,15 @@ pub fn compare<'gc>(
     {
         other_bitmap_data
     } else {
-        // The documentation says that -1 should be returned here, but -2 is actually returned.
+        // The documentation for AVM1 says that -1 should be returned here,
+        // but -2 is actually returned.
+        // TODO: Has this been tested for AVM2?
         return Ok(BITMAP_DISPOSED.into());
     };
     other_bitmap_data.check_valid(activation)?;
 
+    // TODO: Given the above check with `other_bitmap_data.check_valid`, this branch will
+    //   presumably never get executed.
     if other_bitmap_data.disposed() {
         return Ok(BITMAP_DISPOSED.into());
     }
@@ -1369,3 +1373,78 @@ pub fn compare<'gc>(
         None => Ok(EQUIVALENT.into()),
     }
 }
+
+/// Implements `BitmapData.pixelDissolve`.
+pub fn pixel_dissolve<'gc>(
+    activation: &mut Activation<'_, 'gc>,
+    this: Option<Object<'gc>>,
+    args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    if let Some(bitmap_data) = this.and_then(|t| t.as_bitmap_data()) {
+        bitmap_data.check_valid(activation)?;
+
+        let src_bitmap_data = args.get_object(activation, 0, "sourceBitmapData")?;
+
+        let source_rect = args.get_object(activation, 1, "sourceRect")?;
+
+        // TODO: `BitmapData.pixelDissolve() might be called frequently. Is this performant,
+        //   and if not, is there a faster alternative?
+        let src_min_x = source_rect
+            .get_public_property("x", activation)?
+            .coerce_to_i32(activation)?;
+        let src_min_y = source_rect
+            .get_public_property("y", activation)?
+            .coerce_to_i32(activation)?;
+        let src_width = source_rect
+            .get_public_property("width", activation)?
+            .coerce_to_i32(activation)?;
+        let src_height = source_rect
+            .get_public_property("height", activation)?
+            .coerce_to_i32(activation)?;
+
+        let dest_point = args.get_object(activation, 2, "destPoint")?;
+        let dest_point = (
+            dest_point
+                .get_public_property("x", activation)?
+                .coerce_to_i32(activation)?,
+            dest_point
+                .get_public_property("y", activation)?
+                .coerce_to_i32(activation)?,
+        );
+
+        let random_seed = args.get_i32(activation, 3)?;
+
+        let num_pixels = args.get_i32(activation, 4)?;
+        if num_pixels < 0 {
+            return Err(Error::AvmError(range_error(
+                activation,
+                &format!("Parameter numPixels must be a non-negative number; got {num_pixels}."),
+                2027,
+            )?));
+        }
+
+        let fill_color = args.get_i32(activation, 5)?;
+
+        // Apparently, if this check fails, a type error for `null` is given.
+        if let Some(src_bitmap_data) = src_bitmap_data.as_bitmap_data() {
+            src_bitmap_data.check_valid(activation)?;
+
+            return Ok(operations::pixel_dissolve(
+                activation.context.gc_context,
+                bitmap_data,
+                src_bitmap_data,
+                (src_min_x, src_min_y, src_width, src_height),
+                dest_point,
+                random_seed,
+                num_pixels,
+                fill_color,
+            )
+            .into());
+        }
+    }
+
+    // TODO: Should it always return `Ok(Value::Undefined)` in this case?
+    //   Can this even be tested for?
+
+    Ok(Value::Undefined)
+}

core/src/bitmap/operations.rs

@@ -14,6 +14,7 @@ use ruffle_render::filters::Filter;
 use ruffle_render::matrix::Matrix;
 use ruffle_render::quality::StageQuality;
 use ruffle_render::transform::Transform;
+use std::cell::{Ref, RefMut};
 use swf::{BlendMode, ColorTransform, Fixed8, Rectangle, Twips};
 
 /// AVM1 and AVM2 have a shared set of operations they can perform on BitmapDatas.
@@ -1616,3 +1617,244 @@ pub fn set_pixels_from_byte_array<'gc>(
 
     Ok(())
 }
+
+/// Returns at least 2. Always returns an even number.
+fn get_feistel_block_size(sequence_length: u32) -> u32 {
+    let sequence_length = sequence_length.max(2);
+
+    // For the given sequence length, figure out the number of bits required to
+    // represent all indices for the sequence. After that, round up to
+    // the nearest even number of bits.
+    // For instance, for a sequence of length 9, 4 bits are required,
+    // and 4 is even, so the result is 4.
+    // For a sequence of length 8, 3 bits are required, but 3 is not
+    // even, so round up to 4.
+
+    let mut bit_number: u32 = 0;
+    let mut num = sequence_length - 1;
+
+    while num > 0 {
+        num /= 2;
+        bit_number += 1;
+    }
+
+    bit_number + (bit_number % 2)
+}
+
+/// Meant to be a bijective function that takes a raw index and gives the corresponding
+/// Feistel index.
+///
+/// # Arguments
+///
+/// * `raw_permutation_index` - Must obey '0 <= permutation_raw_index < permutation_length`.
+/// * `feistel_block_size` - See `get_feistel_block_size()`.
+fn pixel_dissolve_raw_to_feistel_index(raw_permutation_index: u32, feistel_block_size: u32) -> u32 {
+    // Discussion on Feistel networks:
+    // https://github.com/ruffle-rs/ruffle/issues/10962
+
+    // For the simple balanced variant of a Feistel network, an even number of
+    // bits for the block size is required (unbalanced Feistel networks
+    // also exists, but are presumably more complex).
+
+    // Applying a single round of Feistel.
+
+    let feistel_halfpiece_size = feistel_block_size / 2;
+
+    let halfpiece1 = raw_permutation_index >> feistel_halfpiece_size;
+    let halfpiece2 = raw_permutation_index & ((1 << feistel_halfpiece_size) - 1);
+
+    // Apply some function to make the output appear more random.
+    // TODO: Apply some decent but fast PRNG? Or at least some better and less non-random-looking
+    //   function? Can also take `feistel_block_size` as an argument.
+    // This specific function was gotten by trial-and-error on what might make the output look
+    // random.
+    fn f(num: u32) -> u32 {
+        num * num + 1
+    }
+    let result_before_xor = (f(halfpiece2)) % (1 << feistel_halfpiece_size);
+
+    let new_halfpiece1 = halfpiece2;
+    let new_halfpiece2 = halfpiece1 ^ result_before_xor;
+
+    (new_halfpiece2 << feistel_halfpiece_size) | new_halfpiece1
+}
+
+#[allow(clippy::too_many_arguments)]
+pub fn pixel_dissolve<'gc>(
+    mc: MutationContext<'gc, '_>,
+    target: BitmapDataWrapper<'gc>,
+    source_bitmap: BitmapDataWrapper<'gc>,
+    src_rect: (i32, i32, i32, i32),
+    dest_point: (i32, i32),
+    random_seed: i32,
+    num_pixels: i32,
+    fill_color: i32,
+) -> i32 {
+    // TODO: What should happen in AVM1 when `num_pixels` is negative?
+
+    // Apparently,
+    // "numPixels:int (default = 0) — The default is 1/30 of the source area (width x height). "
+    // is wrong.
+
+    // TODO: Ensure that the AVM1 version returns -1 (probably in the AVM1 interface layer)
+    //   when:
+    //   "Calls to any method or property of a BitmapData object fail if the BitmapData object is
+    //   invalid (for example, if it has height == 0 and width == 0),
+    //   and upon failing those properties and methods that return Number values return -1. ".
+
+    // Extract points and areas.
+
+    let (src_min_x, src_min_y, src_width, src_height) = src_rect;
+
+    let src_width = src_width.max(0);
+    let src_height = src_height.max(0);
+
+    if src_width == 0 || src_height == 0 {
+        return 0;
+    }
+
+    let (dest_min_x, dest_min_y) = dest_point;
+
+    let transparency = target.transparency();
+
+    let mut source_region =
+        PixelRegion::for_whole_size(source_bitmap.width(), source_bitmap.height());
+    let mut dest_region = PixelRegion::for_whole_size(target.width(), target.height());
+    dest_region.clamp_with_intersection(
+        (dest_min_x, dest_min_y),
+        (src_min_x, src_min_y),
+        (src_width, src_height),
+        &mut source_region,
+    );
+
+    if dest_region.width() == 0 || dest_region.height() == 0 {
+        return 0;
+    }
+
+    let write_offset = (dest_region.x_min, dest_region.y_min);
+    let read_offset = (source_region.x_min, source_region.y_min);
+
+    fn write_pixel(
+        write: &mut RefMut<BitmapData>,
+        different_source_than_target: &Option<Ref<BitmapData>>,
+        fill_color: i32,
+        transparency: bool,
+        base_point: (u32, u32),
+        read_offset: (u32, u32),
+        write_offset: (u32, u32),
+    ) {
+        let read_point = (read_offset.0 + base_point.0, read_offset.1 + base_point.1);
+        let write_point = (write_offset.0 + base_point.0, write_offset.1 + base_point.1);
+
+        match different_source_than_target {
+            None => {
+                write.set_pixel32_raw(
+                    write_point.0,
+                    write_point.1,
+                    Color::from(fill_color).to_premultiplied_alpha(transparency),
+                );
+            }
+            Some(different_source) => {
+                write.set_pixel32_raw(
+                    write_point.0,
+                    write_point.1,
+                    different_source.get_pixel32_raw(read_point.0, read_point.1),
+                );
+            }
+        }
+    }
+
+    let different_source_than_target = if source_bitmap.ptr_eq(target) {
+        None
+    } else {
+        Some(source_bitmap.read_area(source_region))
+    };
+
+    let final_pixel_sequence_length = dest_region.width() * dest_region.height();
+
+    let num_pixels = num_pixels.min(final_pixel_sequence_length as i32);
+
+    // TODO: Should this be `target.sync()`? Or something else?
+    let target = target.sync();
+
+    let mut write = target.write(mc);
+
+    // For compliance with the official Flash Player, we always write the pixel at (0, 0).
+    write_pixel(
+        &mut write,
+        &different_source_than_target,
+        fill_color,
+        transparency,
+        (0, 0),
+        read_offset,
+        write_offset,
+    );
+
+    let feistel_block_size: u32 = get_feistel_block_size(final_pixel_sequence_length);
+    let permutation_length = 1 << feistel_block_size;
+    // Raw permutation index.
+    let mut raw_perm_index = (random_seed % (permutation_length as i32)) as u32;
+
+    for _ in 0..num_pixels {
+        // Feistel permutation index.
+        let mut feistel_perm_index = 0;
+
+        // Safety mechanism, in case there is a bug in the implementation.
+        let mut loop_counter = 0;
+
+        // Find a valid index to write to.
+        // Since the pixel at (0, 0) is always written, we always skip `feistel_perm_index == 0`.
+        while (feistel_perm_index == 0 || feistel_perm_index >= final_pixel_sequence_length)
+            && final_pixel_sequence_length != 1
+        {
+            raw_perm_index = (raw_perm_index + 1) % permutation_length;
+
+            feistel_perm_index =
+                pixel_dissolve_raw_to_feistel_index(raw_perm_index, feistel_block_size);
+
+            loop_counter += 1;
+
+            if loop_counter > permutation_length + 2 {
+                // TODO: Is this the correct way to panic or error?
+                panic!(
+                    "operations::pixel_dissolve() failed:\n\
+                            Using Feistel network permutations:\n\
+                            `raw_perm_index`: {raw_perm_index}\n\
+                            `feistel_perm_index`: {feistel_perm_index}\n\
+                            `permutation_length`: {permutation_length}\n\
+                            `final_pixel_sequence_length`: {final_pixel_sequence_length}\n\
+                            `src_rect`: {}, {}, {}, {}\n\
+                            `dest_region`: {}, {}, {}, {}\n\
+                            `dest_point`: {}, {}.",
+                    src_min_x,
+                    src_min_y,
+                    src_width,
+                    src_height,
+                    dest_region.x_min,
+                    dest_region.y_min,
+                    dest_region.x_max,
+                    dest_region.y_max,
+                    dest_point.0,
+                    dest_point.1
+                );
+            }
+        }
+
+        let base_point = (
+            feistel_perm_index % dest_region.width(),
+            feistel_perm_index / dest_region.width(),
+        );
+
+        write_pixel(
+            &mut write,
+            &different_source_than_target,
+            fill_color,
+            transparency,
+            base_point,
+            read_offset,
+            write_offset,
+        );
+    }
+
+    raw_perm_index as i32
+}

tests/tests/swfs/avm2/bitmapdata_pixeldissolve/test.as

@@ -0,0 +1,255 @@
+
+package
+{
+    import flash.display.Sprite;
+    import flash.display.BitmapData;
+    import flash.display.Bitmap;
+    import flash.geom.Point;
+    import flash.geom.Rectangle;
+    import flash.utils.Timer;
+    import flash.events.TimerEvent;
+
+    public class test extends Sprite {
+
+        private function countTraceBitmap(bitmap: BitmapData, round: uint, fillColor: uint = 0xFFFF0000): void {
+
+           var count: int = 0;
+
+           var x: int = 0;
+           while (x < bitmap.width)
+           {
+              var y: int = 0;
+              while (y < bitmap.height)
+              {
+                 if (bitmap.getPixel32(x, y) == fillColor) {
+                    count += 1;
+                 }
+
+                 y += 1;
+              }
+
+              x += 1;
+           }
+
+           trace("(" + round + ") Overwritten pixel count: " + count);
+        }
+
+        private function dissolveOnce(bitmap: BitmapData, rectangle: Rectangle, destPoint: Point, rand: Number, numPixels: Number): Number {
+            var red:uint = 0xFFFF0000;
+            var newRand: Number = bitmap.pixelDissolve(bitmap, rectangle, destPoint, rand, numPixels, red);
+            return newRand;
+        }
+
+        private function dissolveRounds(
+            rounds: uint,
+            width: uint, height: uint,
+            useBitmapDataOwnRectangle: Boolean,
+            sourceRect: Rectangle,
+            destPoint: Point,
+            numPixels: int
+        ): void {
+
+            rounds = Math.max(1, rounds);
+
+            var sourceRectString: String = useBitmapDataOwnRectangle ? "sourceRect: [own]" : "sourceRect: " + sourceRect;
+
+            trace("Dissolving for " + rounds + " rounds, with data: width: " + width + ", height: " + height + ", " + sourceRectString + ", destPoint: " + destPoint + ", numPixels: " + numPixels);
+
+            var bmd2:BitmapData = new BitmapData(width, height, false, 0xFFCCCCCC);
+
+            var round:int;
+            var randNum: Number = 0;
+            for (round = 1; round <= rounds; round++)
+            {
+                randNum = dissolveOnce(bmd2, useBitmapDataOwnRectangle ? bmd2.rect : sourceRect, destPoint, randNum, numPixels);
+                countTraceBitmap(bmd2, round);
+            }
+
+            trace("");
+        }
+
+        private function dissolveRounds_1(
+            rounds: uint,
+            width: uint, height: uint,
+            numPixels: int
+        ): void {
+            dissolveRounds(rounds, width, height, true, null, new Point(0, 0), numPixels);
+        }
+
+        private function dissolveRounds_2(
+            rounds: uint,
+            width: uint, height: uint,
+            sourceRect: Rectangle,
+            numPixels: int
+        ): void {
+            dissolveRounds(rounds, width, height, false, sourceRect, new Point(0, 0), numPixels);
+        }
+
+        private function dissolveRounds_3(
+            rounds: uint,
+            width: uint, height: uint,
+            sourceRect: Rectangle,
+            destPoint: Point,
+            numPixels: int
+        ): void {
+            dissolveRounds(rounds, width, height, false, sourceRect, destPoint, numPixels);
+        }
+
+        public function test() {
+
+            trace("------------------------------------------");
+            trace("Basic test.");
+            trace("");
+            dissolveRounds_1(100, 10, 10, 1);
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("`numPixels`.");
+            trace("");
+            dissolveRounds_1(4, 10, 10, 0);
+            try {
+                dissolveRounds_1(4, 10, 10, -1);
+            }
+            catch (e:Error) {
+                trace("Negative `numPixels` should error.");
+            }
+            dissolveRounds_1(35, 10, 10, 3);
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("Dimensions.");
+            trace("");
+            // WARNING: Apparently, `width` or `height` being 1 means that nothing is written,
+            // not even the pixel at (0, 0). This seems like a bug in Flash Player and will
+            // not necessarily be emulated. So, do not test for it here.
+            dissolveRounds_1(61, 150, 2, 5);
+            dissolveRounds_1(61, 2, 150, 5);
+            dissolveRounds_1(66, 8, 8, 1);
+            dissolveRounds_1(66, 7, 9, 1); // 7*9 = 8*8 - 1.
+            dissolveRounds_1(66, 5, 13, 1); // 5*13 = 8*8 + 1.
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("`sourceRect`.");
+            trace("");
+            dissolveRounds_2(101, 10, 10, new Rectangle(0, 0, 10, 10), 1);
+            dissolveRounds_2(20, 10, 10, new Rectangle(0, 0, 4, 4), 1);
+            dissolveRounds_2(35, 10, 10, new Rectangle(0, 0, 8, 4), 1);
+            dissolveRounds_2(35, 10, 10, new Rectangle(0, 0, 4, 8), 1);
+            dissolveRounds_2(27, 10, 10, new Rectangle(0, 0, 3, 8), 1);
+            dissolveRounds_2(31, 10, 10, new Rectangle(0, 0, 4, 7), 1);
+            dissolveRounds_2(24, 10, 10, new Rectangle(0, 0, 3, 7), 1);
+            dissolveRounds_2(30, 10, 10, new Rectangle(1, 3, 4, 8), 1);
+            dissolveRounds_2(4, 10, 10, new Rectangle(14, 3, 4, 8), 1);
+            dissolveRounds_2(4, 10, 10, new Rectangle(3, 14, 4, 8), 1);
+            dissolveRounds_2(25, 10, 10, new Rectangle(-1, 3, 4, 8), 1);
+            dissolveRounds_2(25, 10, 10, new Rectangle(-1, -1, 4, 8), 1);
+            dissolveRounds_2(30, 10, 10, new Rectangle(2, -1, 4, 8), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, -1, -3), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, -1, 3), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, 1, -3), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, 0, 1), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, 1, 0), 1);
+            dissolveRounds_2(2, 10, 10, new Rectangle(1, 2, 0, 0), 1);
+            // Note: Apparently, Flash Player seems to round width and height
+            // in really peculiar ways when the x- and y-coordinates have
+            // fractional components. Therefore, the tests involving
+            // fractional parts are commented out.
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 0.5, 3, 3), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 0.5, 3, 4), 1);
+            //dissolveRounds_2(27, 10, 10, new Rectangle(0.5, 0.5, 3, 5), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 0.5, 4, 3), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 0.5, 4, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(0.4, 1, 3, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(0.6, 1, 3, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(1, 1, 3.4, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(1, 1, 3.5, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(1, 1, 3.6, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.4, 1, 3.4, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 1, 3.4, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(0.6, 1, 3.4, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.4, 1, 3.5, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 1, 3.5, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(0.6, 1, 3.5, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.4, 1, 3.6, 4), 1);
+            //dissolveRounds_2(18, 10, 10, new Rectangle(0.5, 1, 3.6, 4), 1);
+            //dissolveRounds_2(14, 10, 10, new Rectangle(0.6, 1, 3.6, 4), 1);
+            try {
+                dissolveRounds_2(20, 10, 10, null, 1);
+            }
+            catch (e: Error) {
+                trace("`null` `sourceRect` should error: " + e);
+            }
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("`destPoint`.");
+            trace("");
+            dissolveRounds_3(18, 10, 10, new Rectangle(0, 0, 3, 7), new Point(3, 5), 1);
+            // This would result in a 1x6 resulting area. And Flash Player's pixelDissolve()
+            // cannot handle a size where at least one of the dimensions is 1.
+            //dissolveRounds_3(8, 10, 10, new Rectangle(0, 0, 3, 7), new Point(-2, -1), 1);
+            dissolveRounds_3(15, 10, 10, new Rectangle(0, 0, 3, 7), new Point(-1, -1), 1);
+            dissolveRounds_3(3, 10, 10, new Rectangle(0, 0, 3, 7), new Point(-10, -10), 1);
+            dissolveRounds_3(3, 10, 10, new Rectangle(0, 0, 3, 7), new Point(-2, 10), 1);
+            dissolveRounds_3(21, 10, 10, new Rectangle(0, 0, 3, 7), new Point(5, 4),1);
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("Default parameters.");
+            trace("");
+            var bmd:BitmapData = new BitmapData(10, 10, false, 0xFFCCCCCC);
+            // Omitting `numPixels` and `fillColor`.
+            // Apparently, "numPixels:int (default = 0) — The default is 1/30 of the source area (width x height). " is wrong.
+            bmd.pixelDissolve(bmd, bmd.rect, new Point(0, 0));
+            countTraceBitmap(bmd, 0, 0xFF000000);
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("`null` `sourceBitmapData`.");
+            trace("");
+            var bmd2:BitmapData = new BitmapData(10, 10, false, 0xFFCCCCCC);
+            try {
+                bmd2.pixelDissolve(null, bmd2.rect, new Point(0, 0));
+            }
+            catch (e: Error) {
+                trace("`sourceBitmapData` being `null` should result in error: " + e);
+            }
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("`null` `sourceBitmapData`.");
+            trace("");
+            var bmd3:BitmapData = new BitmapData(10, 10, false, 0xFFCCCCCC);
+            try {
+                bmd3.pixelDissolve(5 as BitmapData, bmd3.rect, new Point(0, 0));
+            }
+            catch (e: Error) {
+                trace("`sourceBitmapData` being the wrong type should result in error: " + e);
+            }
+
+            trace("");
+            trace("");
+            trace("------------------------------------------");
+            trace("Invalid other bitmap.");
+            trace("");
+            var bmd4:BitmapData = new BitmapData(10, 10, false, 0xFFCCCCCC);
+            var bmd5:BitmapData = new BitmapData(10, 10, false, 0xFFCFFCCC);
+            bmd5.dispose();
+            try {
+                bmd4.pixelDissolve(bmd5, bmd4.rect, new Point(0, 0));
+            }
+            catch (e: Error) {
+                trace("`sourceBitmapData` being disposed() should result in error: " + e);
+            }
+        }
+    }
+}
+

tests/tests/swfs/avm2/bitmapdata_pixeldissolve/test.toml

@@ -0,0 +1 @@
+num_frames = 1

tests/tests/swfs/avm2/bitmapdata_pixeldissolve_image/test.as

@@ -0,0 +1,121 @@
+
+package
+{
+    import flash.display.Sprite;
+    import flash.display.BitmapData;
+    import flash.display.Bitmap;
+    import flash.geom.Point;
+    import flash.geom.Rectangle;
+    import flash.utils.Timer;
+    import flash.events.TimerEvent;
+
+    public class test extends Sprite {
+
+        private function add(bitmapData: BitmapData, x: Number, y: Number): void {
+
+            var destBitmap:Bitmap = new Bitmap(bitmapData);
+            destBitmap.x = x;
+            destBitmap.y = y;
+            this.addChild(destBitmap);
+        }
+
+        public function test() {
+
+            var x: uint;
+            var y: uint;
+
+            /////////////////////////////////////////////////////////////////
+            // Transparency.
+            /////////////////////////////////////////////////////////////////
+
+            function sourceHandlingOpaque(dest: BitmapData, x: Number, y: Number): void {
+                dest.pixelDissolve(dest, dest.rect, new Point(0, 0), 0, 9999, 0xFF33FF99);
+                add(dest, x, y);
+            }
+
+            function sourceHandlingSemiTransparent(dest: BitmapData, x: Number, y: Number): void {
+                dest.pixelDissolve(dest, dest.rect, new Point(0, 0), 0, 9999, 0xAA5511FF);
+                add(dest, x, y);
+            }
+
+            function sourceHandlingCompletelyTransparent(dest: BitmapData, x: Number, y: Number): void {
+                dest.pixelDissolve(dest, dest.rect, new Point(0, 0), 0, 9999, 0x003377FF);
+                add(dest, x, y);
+            }
+
+            var sourceBitmapData4:BitmapData = new BitmapData(100, 100, true, 0xFFFFAA33);
+            for (x = 0; x < 100; x += 1) {
+                for (y = 0; y < 20; y += 1) {
+                    sourceBitmapData4.setPixel32(x, y, 0x00FFAA00);
+                }
+            }
+            for (x = 0; x < 100; x += 1) {
+                for (y = 20; y < 40; y += 1) {
+                    sourceBitmapData4.setPixel32(x, y, 0x88337777);
+                }
+            }
+            function sourceHandlingMixedBitmapSource(dest: BitmapData, x: Number, y: Number): void {
+                dest.pixelDissolve(sourceBitmapData4, dest.rect, new Point(0, 0), 0, 9999);
+                add(dest, x, y);
+            }
+
+            function destOpaque(): BitmapData {
+                return new BitmapData(100, 100, true, 0xFF1199DD);
+            }
+
+            function destSemiTransparent(): BitmapData {
+                return new BitmapData(100, 100, true, 0xAA44BB11);
+            }
+
+            function destCompletelyTransparent(): BitmapData {
+                return new BitmapData(100, 100, true, 0x0000DD44);
+            }
+
+            var destFactories: Array = [
+                destOpaque,
+                destSemiTransparent,
+                destCompletelyTransparent
+            ];
+            var sourceHandlings: Array = [
+                sourceHandlingOpaque,
+                sourceHandlingSemiTransparent,
+                sourceHandlingCompletelyTransparent,
+                sourceHandlingMixedBitmapSource
+            ];
+
+            for (x = 0; x < sourceHandlings.length; x += 1) {
+                for (y = 0; y < destFactories.length; y += 1) {
+                    // Create a fresh destination BitmapData, call `pixelDissolve` on it with the given source, and place it at (x*100, y*100).
+                    sourceHandlings[x](destFactories[y](), x*100, y*100);
+                }
+            }
+
+            /////////////////////////////////////////////////////////////////
+            // Source and destination offsets and areas.
+            /////////////////////////////////////////////////////////////////
+
+            var offsetBitmapData: BitmapData = new BitmapData(100, 100, false, 0xFF000000);
+            var offsetBitmapData2: BitmapData = new BitmapData(100, 100, false, 0xFF000000);
+            for (x = 0; x < 100; x += 1) {
+                for (y = 0; y < 100; y += 1) {
+                    offsetBitmapData.setPixel(x, y, x + y + 0x990000);
+                    offsetBitmapData2.setPixel(x, y, x + y + 0x009900);
+                }
+            }
+            offsetBitmapData2.pixelDissolve(offsetBitmapData, new Rectangle(30, 40, 35, 55), new Point(25, 10), 0, 9999);
+            add(offsetBitmapData2, 400, 0);
+
+            var offsetBitmapData3: BitmapData = new BitmapData(100, 100, false, 0xFF000000);
+            var offsetBitmapData4: BitmapData = new BitmapData(100, 100, false, 0xFF000000);
+            for (x = 0; x < 100; x += 1) {
+                for (y = 0; y < 100; y += 1) {
+                    offsetBitmapData3.setPixel(x, y, x - y + 0x990000);
+                    offsetBitmapData4.setPixel(x, y, x + y + 0x009900);
+                }
+            }
+            offsetBitmapData4.pixelDissolve(offsetBitmapData3, new Rectangle(30, 40, 35, 55), new Point(25, 10), 0, 9999);
+            add(offsetBitmapData4, 400, 100);
+        }
+    }
+}
+

tests/tests/swfs/avm2/bitmapdata_pixeldissolve_image/test.toml

@@ -0,0 +1,7 @@
+num_frames = 1
+
+[image_comparison]
+tolerance = 1
+
+[player_options]
+with_renderer = { optional = false, sample_count = 1 }