tiny.gui.paint.regions

1const paint = @import("root.zig");23const Bounds = paint.cpu.Bounds;4const Rect = @import("../root.zig").layout.Rect;5const Region = paint.cpu.Region;67pub const capacity: usize = 8;89pub const Set = struct {10    items: [capacity]Region = undefined,11    len: usize = 0,1213    pub fn clear(self: *Set) void {14        self.len = 0;15    }1617    pub fn append(self: *Set, region: Region) void {18        if (self.len < self.items.len) {19            self.items[self.len] = region;20            self.len += 1;21            return;22        }23        const collapsed = unite(self.bounding().?, region);24        self.items[0] = collapsed;25        self.len = 1;26    }2728    pub fn slice(self: *const Set) []const Region {29        return self.items[0..self.len];30    }3132    pub fn pixelCount(self: Set) usize {33        var count: usize = 0;34        for (self.items[0..self.len]) |region| {35            count +|= region.pixelCount();36        }37        return count;38    }3940    pub fn bounding(self: Set) ?Region {41        if (self.len == 0) return null;42        var result = self.items[0];43        for (self.items[1..self.len]) |region| {44            result = unite(result, region);45        }46        return result;47    }48};4950pub fn fromBounds(51    bounds: Bounds,52    margin: u32,53    width: u32,54    height: u32,55) Region {56    const x0 = @min(bounds.x0 -| margin, width);57    const y0 = @min(bounds.y0 -| margin, height);58    const x1 = @min(bounds.x1 +| margin, width);59    const y1 = @min(bounds.y1 +| margin, height);60    if (x0 >= x1 or y0 >= y1) return .{ .x = x0, .y = y0 };61    return .{62        .x = x0,63        .y = y0,64        .width = x1 - x0,65        .height = y1 - y0,66    };67}6869pub fn fromRect(70    rect: Rect,71    margin: u32,72    width: u32,73    height: u32,74) ?Region {75    if (rect.width <= 0 or rect.height <= 0) return null;76    const geometry = paint.cpu.geometry;77    const x0 = geometry.floorClamp(rect.x, width);78    const y0 = geometry.floorClamp(rect.y, height);79    const x1 = geometry.ceilClamp(rect.x + rect.width, width);80    const y1 = geometry.ceilClamp(rect.y + rect.height, height);81    if (x0 >= x1 or y0 >= y1) return null;82    return fromBounds(.{ .x0 = x0, .y0 = y0, .x1 = x1, .y1 = y1 }, margin, width, height);83}8485pub fn unite(left: Region, right: Region) Region {86    const x0 = @min(left.x, right.x);87    const y0 = @min(left.y, right.y);88    const x1 = @max(left.x +| left.width, right.x +| right.width);89    const y1 = @max(left.y +| left.height, right.y +| right.height);90    return .{91        .x = x0,92        .y = y0,93        .width = x1 - x0,94        .height = y1 - y0,95    };96}9798pub fn intersect(left: Region, right: Region) Region {99    const x0 = @max(left.x, right.x);100    const y0 = @max(left.y, right.y);101    const x1 = @min(left.x +| left.width, right.x +| right.width);102    const y1 = @min(left.y +| left.height, right.y +| right.height);103    if (x0 >= x1 or y0 >= y1) return .{ .x = x0, .y = y0 };104    return .{105        .x = x0,106        .y = y0,107        .width = x1 - x0,108        .height = y1 - y0,109    };110}111112test "region set collapses overflow without losing damage" {113    var regions = Set{};114    for (0..capacity + 1) |index| {115        regions.append(.{116            .x = @intCast(index * 2),117            .width = 1,118            .height = 1,119        });120    }121122    try @import("std").testing.expectEqual(@as(usize, 1), regions.len);123    try @import("std").testing.expectEqual(124        Region{ .x = 0, .width = capacity * 2 + 1, .height = 1 },125        regions.bounding().?,126    );127}128129test "bounds outside the target collapse to an empty edge region" {130    const std = @import("std");131    try std.testing.expectEqual(132        Region{ .x = 16, .y = 4 },133        fromBounds(134            .{ .x0 = 20, .y0 = 4, .x1 = 30, .y1 = 8 },135            0,136            16,137            16,138        ),139    );140    try std.testing.expectEqual(141        Region{ .x = 12, .y = 4 },142        fromBounds(143            .{ .x0 = 12, .y0 = 4, .x1 = 8, .y1 = 8 },144            0,145            16,146            16,147        ),148    );149}

1pub const regions = @import("regions.zig");