tiny.gif.EncodePlan

1pub const Plan = struct {2    input_hash: u64,3    width: u32,4    height: u32,5    canvas_pixels: usize,6    frames: usize,7    palette_entries: usize,8    table_entries: usize,9    max_compressed_bytes: usize,10    output_bytes: usize,11    bounds: Bounds,12    palette: model.Palette,1314    pub fn inspect(15        animation: model.AnimationView,16        bounds: Bounds,17        scratch: *lzw.Scratch,18    ) Error!Plan {19        return inspectDictionary(animation, bounds, scratch.dictionary());20    }2122    pub fn inspectDictionary(23        animation: model.AnimationView,24        bounds: Bounds,25        dictionary: lzw.Dictionary,26    ) Error!Plan {27        if (animation.width == 0 or animation.height == 0) return error.InvalidDimensions;28        if (animation.width > std.math.maxInt(u16) or animation.height > std.math.maxInt(u16)) {29            return error.InvalidDimensions;30        }31        if (animation.frames.len == 0) return error.NoFrames;3233        const canvas_pixels = try multiplied(animation.width, animation.height);34        if (canvas_pixels > bounds.canvas_pixels) return error.CanvasPixelCapacityExceeded;35        if (animation.frames.len > bounds.frames) return error.FrameCapacityExceeded;36        const rgba8_bytes = try multiplied(canvas_pixels, 4);37        for (animation.frames) |frame| {38            if (frame.rgba8.len != rgba8_bytes) return error.FrameSizeMismatch;39        }4041        const palette = try model.Palette.build(animation.frames);42        const palette_entries = palette.entryCount();43        if (palette_entries > bounds.palette_entries) return error.PaletteCapacityExceeded;44        const table_entries = palette.tableEntries();45        var output_bytes = try added(13, try multiplied(table_entries, 3));46        if (animation.loop_count != null) output_bytes = try added(output_bytes, 19);4748        var max_compressed_bytes: usize = 0;49        for (animation.frames) |frame| {50            const source = model.PixelSource{ .palette = &palette, .rgba8 = frame.rgba8 };51            const compressed = try lzw.measureSource(palette.minCodeSize(), source, dictionary);52            max_compressed_bytes = @max(max_compressed_bytes, compressed);53            output_bytes = try added(output_bytes, try frameBytes(compressed));54        }55        output_bytes = try added(output_bytes, 1);5657        return .{58            .input_hash = animationHash(animation),59            .width = animation.width,60            .height = animation.height,61            .canvas_pixels = canvas_pixels,62            .frames = animation.frames.len,63            .palette_entries = palette_entries,64            .table_entries = table_entries,65            .max_compressed_bytes = max_compressed_bytes,66            .output_bytes = output_bytes,67            .bounds = bounds,68            .palette = palette,69        };70    }7172    pub fn exactBounds(self: Plan) Bounds {73        return .{74            .canvas_pixels = self.canvas_pixels,75            .frames = self.frames,76            .palette_entries = self.palette_entries,77        };78    }79};

1pub const EncodePlan = encode.Plan;