fix layouting

Author: zenith391

examples/border-layout.zig

@@ -3,7 +3,7 @@ const capy = @import("capy");
 pub usingnamespace capy.cross_platform;
 
 pub fn main() !void {
-    try capy.backend.init();
+    try capy.init();
 
     var window = try capy.Window.init();
     try window.set(capy.column(.{}, .{

src/components/Alignment.zig

@@ -94,8 +94,8 @@ pub const Alignment = struct {
                 const preferred_size = self.child.get().getPreferredSize(available);
                 const final_size = Size.intersect(preferred_size, available);
 
-                const x: u32 = @intFromFloat(alignX * available.width - final_size.width);
-                const y: u32 = @intFromFloat(alignY * available.height - final_size.height);
+                const x: u32 = @intFromFloat(alignX * @max(0, available.width - final_size.width));
+                const y: u32 = @intFromFloat(alignY * @max(0, available.height - final_size.height));
 
                 peer.move(widget_peer, x, y);
                 peer.resize(widget_peer, @intFromFloat(final_size.width), @intFromFloat(final_size.height));

src/containers.zig

@@ -48,7 +48,7 @@ pub fn ColumnLayout(peer: Callbacks, widgets: []*Widget) void {
     const config = peer.getLayoutConfig(ColumnRowConfig);
     const spacing: f32 = @floatFromInt(config.spacing);
 
-    const totalAvailableHeight = peer.getSize(peer.userdata).height - @as(f32, @floatFromInt((widgets.len -| 1) * config.spacing));
+    const totalAvailableHeight: f32 = @max(0, peer.getSize(peer.userdata).height - @as(f32, @floatFromInt((widgets.len -| 1) * config.spacing)));
 
     var childHeight = if (expandedCount == 0) 0 else totalAvailableHeight / @as(f32, @floatFromInt(expandedCount));
     for (widgets) |widget| {
@@ -81,7 +81,7 @@ pub fn ColumnLayout(peer: Callbacks, widgets: []*Widget) void {
 
             const available = Size{
                 .width = peer.getSize(peer.userdata).width,
-                .height = if (widget.container_expanded) childHeight else peer.getSize(peer.userdata).height - childY,
+                .height = if (widget.container_expanded) childHeight else @max(0, peer.getSize(peer.userdata).height - childY),
             };
             const preferred = widget.getPreferredSize(available);
             const size = blk: {
@@ -124,7 +124,7 @@ pub fn RowLayout(peer: Callbacks, widgets: []*Widget) void {
     const config = peer.getLayoutConfig(ColumnRowConfig);
     const spacing: f32 = @floatFromInt(config.spacing);
 
-    const totalAvailableWidth = peer.getSize(peer.userdata).width - @as(f32, @floatFromInt((widgets.len -| 1) * config.spacing));
+    const totalAvailableWidth: f32 = @max(0, peer.getSize(peer.userdata).width - @as(f32, @floatFromInt((widgets.len -| 1) * config.spacing)));
 
     var childWidth = if (expandedCount == 0) 0 else totalAvailableWidth / @as(f32, @floatFromInt(expandedCount));
     for (widgets) |widget| {
@@ -156,7 +156,7 @@ pub fn RowLayout(peer: Callbacks, widgets: []*Widget) void {
             }
 
             const available = Size{
-                .width = if (widget.container_expanded) childWidth else peer.getSize(peer.userdata).width - childX,
+                .width = if (widget.container_expanded) childWidth else @max(0, peer.getSize(peer.userdata).width - childX),
                 .height = peer.getSize(peer.userdata).height,
             };
             const preferred = widget.getPreferredSize(available);