From 836d7669e58581af72b98fa802962a597fd66a13 Mon Sep 17 00:00:00 2001
From: Yves Biener <yves.biener@gmx.de>
Date: Sun, 18 Jan 2026 13:36:03 +0100
Subject: [PATCH] feat: introduce growth options `.horizontal_only` and
 `.vertical_only`

Growing containers only in one specific direction while fixing the
other dimension (which is then required to be provided - just like
before).
---
 src/container.zig | 28 +++++++++++++++++++---------
 src/element.zig   |  4 ++--
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/container.zig b/src/container.zig
index e773fa5..1a0b069 100644
--- a/src/container.zig
+++ b/src/container.zig
@@ -599,9 +599,11 @@ pub const Layout = packed struct {
 /// Sizing options which should be used by the `Container`
 pub const Size = packed struct {
     dim: Point = .{},
-    grow: enum(u2) {
+    grow: enum(u3) {
         both,
         fixed,
+        vertical_only,
+        horizontal_only,
         vertical,
         horizontal,
     } = .both,
@@ -732,11 +734,11 @@ pub fn Container(Model: type, Event: type) type {
                     assert(this.properties.size.dim.y > 0 or size.y > 0);
                     break :blk .max(size, this.properties.size.dim);
                 },
-                .horizontal => blk: {
+                .horizontal, .horizontal_only => blk: {
                     assert(this.properties.size.dim.y > 0 or size.y > 0);
                     break :blk .max(size, this.properties.size.dim);
                 },
-                .vertical => blk: {
+                .vertical, .vertical_only => blk: {
                     assert(this.properties.size.dim.x > 0 or size.x > 0);
                     break :blk .max(size, this.properties.size.dim);
                 },
@@ -799,21 +801,21 @@ pub fn Container(Model: type, Event: type) type {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
-                    .horizontal => if (layout.direction == .horizontal) {
+                    .horizontal, .horizontal_only => if (layout.direction == .horizontal) {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
-                    .vertical => if (layout.direction == .vertical) {
+                    .vertical, .vertical_only => if (layout.direction == .vertical) {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
                 }
                 // non layout direction side growth
                 switch (layout.direction) {
-                    .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .both) {
+                    .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .vertical_only or child.properties.size.grow == .both) {
                         child.size.y = available;
                     },
-                    .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .both) {
+                    .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .vertical_only or child.properties.size.grow == .both) {
                         child.size.x = available;
                     },
                 }
@@ -831,8 +833,8 @@ pub fn Container(Model: type, Event: type) type {
                     if (child.properties.size.grow == .fixed) continue;
 
                     switch (layout.direction) {
-                        .horizontal => if (child.properties.size.grow == .vertical) continue,
-                        .vertical => if (child.properties.size.grow == .horizontal) continue,
+                        .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .vertical_only) continue,
+                        .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .horizontal_only) continue,
                     }
 
                     const size = switch (layout.direction) {
@@ -898,6 +900,14 @@ pub fn Container(Model: type, Event: type) type {
             this.size = switch (this.properties.size.grow) {
                 .both => .max(size, fit_size),
                 .fixed => fit_size,
+                .horizontal_only => .{
+                    .x = size.x,
+                    .y = fit_size.y,
+                },
+                .vertical_only => .{
+                    .x = fit_size.x,
+                    .y = size.y,
+                },
                 .horizontal => .{
                     .x = @max(size.x, fit_size.x),
                     .y = size.y,
diff --git a/src/element.zig b/src/element.zig
index 6d9e580..fcda7ee 100644
--- a/src/element.zig
+++ b/src/element.zig
@@ -219,8 +219,8 @@ pub fn Alignment(Model: type, Event: type) type {
             outer: for (0..csize.y) |row| {
                 inner: for (0..csize.x) |col| {
                     // do not read/write out of bounce
-                    if (this.size.x < row) break :outer;
-                    if (this.size.y < col) break :inner;
+                    if (this.size.y < row) break :outer;
+                    if (this.size.x < col) break :inner;
 
                     cells[((row + origin.y) * size.x) + col + origin.x] = container_cells[(row * csize.x) + col];
                 }