fix(container/layout): padding calculation for anchor corrections

examples/container.zig

@@ -31,20 +31,32 @@ pub fn main() !void {
             .separator = .{ .enabled = false },
         },
         .layout = .{
-            .gap = 1,
             .padding = .all(5),
-            .direction = .horizontal,
+            .direction = .vertical,
         },
     });
-    try container.append(try App.Container.init(allocator, .{
+    var box = try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .blue },
         .layout = .{
+            .gap = 1,
+            .direction = .horizontal,
+            .padding = .vertical(1),
             .sizing = .{
-                .width = .{ .fixed = 70 },
+                // .width = .{ .fixed = 700 },
-                .height = .{ .fixed = 18 },
+                // .height = .{ .fixed = 180 },
             },
         },
+    });
+    try box.append(try App.Container.init(allocator, .{
+        .rectangle = .{ .fill = .light_green },
     }));
+    try box.append(try App.Container.init(allocator, .{
+        .rectangle = .{ .fill = .light_green },
+    }));
+    try box.append(try App.Container.init(allocator, .{
+        .rectangle = .{ .fill = .light_green },
+    }));
+    try container.append(box);
     try container.append(try App.Container.init(allocator, .{
         .border = .{ .color = .light_blue, .corners = .squared },
     }));

src/container.zig

@@ -311,6 +311,7 @@ pub fn Container(comptime Event: type) type {
                     });
                     this.viewport = s;
                     // sizing
+                    // FIX: fixed sizing for smaller and bigger values does not work yet
                     var size = s;
                     size.anchor = .{}; // reset relative anchor of size!
                     const sizing = this.properties.layout.sizing;
@@ -410,16 +411,21 @@ pub fn Container(comptime Event: type) type {
                                 }
                                 element_size = .{
                                     .anchor = .{
-                                        .col = size.anchor.col + offset,
+                                        .col = this.viewport.anchor.col + offset,
-                                        .row = size.anchor.row,
+                                        .row = this.viewport.anchor.row,
                                     },
                                     .cols = cols,
                                     .rows = size.rows,
                                 };
+                                // border
                                 if (sides.top) element_size.rows -= 1;
                                 if (sides.bottom) element_size.rows -= 1;
-                                offset += cols;
+                                // padding
+                                element_size.anchor.row += padding.top;
+                                element_size.rows -= padding.top + padding.bottom;
+                                // gap
                                 offset += gap;
+                                offset += cols;
                             },
                             .vertical => {
                                 var rows = element_rows;
@@ -429,16 +435,21 @@ pub fn Container(comptime Event: type) type {
                                 }
                                 element_size = .{
                                     .anchor = .{
-                                        .col = size.anchor.col,
+                                        .col = this.viewport.anchor.col,
-                                        .row = size.anchor.row + offset,
+                                        .row = this.viewport.anchor.row + offset,
                                     },
                                     .cols = size.cols,
                                     .rows = rows,
                                 };
+                                // border
                                 if (sides.left) element_size.cols -= 1;
                                 if (sides.right) element_size.cols -= 1;
-                                offset += rows;
+                                // padding
+                                element_size.anchor.col += padding.left;
+                                element_size.cols -= padding.left + padding.right;
+                                // gap
                                 offset += gap;
+                                offset += rows;
                             },
                         }
 
@@ -451,10 +462,6 @@ pub fn Container(comptime Event: type) type {
                         }
 
                         // padding resizing
-                        element_size.anchor.row += padding.top;
-                        element_size.anchor.col += padding.left;
-                        element_size.rows -= padding.top + padding.bottom;
-                        element_size.cols -= padding.left + padding.right;
 
                         try element.handle(.{ .resize = element_size });
                     }
@@ -464,52 +471,58 @@ pub fn Container(comptime Event: type) type {
         }
 
         pub fn contents(this: *const @This()) ![]const Cell {
-            const content = try this.allocator.alloc(Cell, @as(usize, this.properties.scroll.size.cols) * @as(usize, this.properties.scroll.size.rows));
+            const content_cells = try this.allocator.alloc(Cell, @as(usize, this.properties.scroll.size.cols) * @as(usize, this.properties.scroll.size.rows));
-            defer this.allocator.free(content);
+            defer this.allocator.free(content_cells);
-            @memset(content, .{});
+            @memset(content_cells, .{});
 
-            const cells = try this.allocator.alloc(Cell, @as(usize, this.viewport.cols) * @as(usize, this.viewport.rows));
+            const viewport_cells = try this.allocator.alloc(Cell, @as(usize, this.viewport.cols) * @as(usize, this.viewport.rows));
-            @memset(cells, .{});
+            @memset(viewport_cells, .{});
 
-            this.properties.border.contents(content, this.properties.scroll.size, this.properties.layout, @truncate(this.elements.items.len));
+            this.properties.border.contents(content_cells, this.properties.scroll.size, this.properties.layout, @truncate(this.elements.items.len));
-            this.properties.rectangle.contents(content, this.properties.scroll.size);
+            this.properties.rectangle.contents(content_cells, this.properties.scroll.size);
 
-            const cols = blk: {
+            log.debug("Content::contents .scroll.size: {{ .anchor = {{ .col = {d}, .row = {d} }}, .cols = {d}, .rows = {d} }}", .{
-                var cols: u16 = this.properties.scroll.size.cols;
-                if (this.properties.scroll.size.cols > this.viewport.cols) {
-                    cols = this.viewport.cols;
-                }
-                break :blk cols;
-            };
-            const rows = blk: {
-                var rows: u16 = this.properties.scroll.size.rows;
-                if (this.properties.scroll.size.rows > this.viewport.rows) {
-                    rows = this.viewport.rows;
-                }
-                break :blk rows;
-            };
-            const anchor = (this.properties.scroll.size.anchor.row * this.properties.scroll.size.cols) + this.properties.scroll.size.anchor.col;
-            log.debug("viewport = .{{ .anchor = {{ .col = {d}, .row = {d} }}, .cols = {d}, .rows = {d} }}", .{
-                this.viewport.anchor.col,
-                this.viewport.anchor.row,
-                this.viewport.cols,
-                this.viewport.rows,
-            });
-            log.debug("size = .{{ .anchor = {{ .col = {d}, .row = {d} }}, .cols = {d}, .rows = {d} }}", .{
                 this.properties.scroll.size.anchor.col,
                 this.properties.scroll.size.anchor.row,
                 this.properties.scroll.size.cols,
                 this.properties.scroll.size.rows,
             });
-            for (0..rows) |row| {
+
-                for (0..cols) |col| {
+            const cols = blk: {
-                    // TODO: try to do this with @memcpy instead to improve performance
+                var cols: u16 = this.properties.scroll.size.cols - this.properties.scroll.size.anchor.col;
-                    const cell = content[anchor + (row * this.properties.scroll.size.cols) + col];
+                if (cols > this.viewport.cols) {
-                    cells[row * this.viewport.cols + col].cp = cell.cp;
+                    cols = this.viewport.cols;
-                    cells[row * this.viewport.cols + col].style = cell.style;
                 }
+                break :blk cols;
+            };
+            const rows = blk: {
+                var rows: u16 = this.properties.scroll.size.rows - this.properties.scroll.size.anchor.col;
+                if (rows > this.viewport.rows) {
+                    rows = this.viewport.rows;
+                }
+                break :blk rows;
+            };
+
+            var content_row: usize = this.properties.scroll.size.anchor.row;
+            var content_col: usize = this.properties.scroll.size.anchor.col;
+            var viewport_row: usize = 0;
+            var viewport_col: usize = 0;
+
+            for (0..rows) |_| {
+                for (0..cols) |_| {
+                    // TODO: try to do this with @memcpy instead to improve performance
+                    const cell = content_cells[(content_row * this.properties.scroll.size.cols) + content_col];
+                    viewport_cells[(viewport_row * this.viewport.cols) + viewport_col] = cell;
+
+                    content_col += 1;
+                    viewport_col += 1;
+                }
+                content_row += 1;
+                viewport_row += 1;
+                content_col = 0;
+                viewport_col = 0;
             }
-            return cells;
+            return viewport_cells;
         }
     };
 }