1 files changed, 146 insertions, 0 deletions

diff --git a/src/layout.c b/src/layout.c
new file mode 100644
index 0000000..9d4b556
--- /dev/null
+++ b/src/layout.c
@@ -0,0 +1,146 @@
+#include <ui.h>
+
+#include "uiLibrary.h"
+#include "widget/table.h"
+#include "widget/widget.h"
+
+#include <cassert.h>
+
+static void ResizeTable(uiTable* table, int width, int height) {
+  assert(table);
+
+  if (table->cols == 0) {
+    return;
+  }
+
+  // Determine if there is vertical overflow. This determines whether we need to
+  // render a scroll bar, in which case room must be made for it.
+  table->flags.vertical_overflow =
+      (table->rows * g_ui.font->header.glyph_height) >
+      table->widget.rect.height;
+
+  // Surface width: W.
+  // Columns: N
+  //
+  // First, find the minimum width of each column based on their contents.
+  //
+  // If the sum of column widths < N, then distribute the extra space first
+  // among the smallest columns and building up towards the larger.
+  //
+  // If the sum of column widths > N, subtract from the largest column first and
+  // move towards the smaller ones to distribute the space as evenly as
+  // possible.
+
+  // Find the minimum width for each column.
+  int* widths = table->widths;
+  // Header.
+  for (int col = 0; col < table->cols; ++col) {
+    const uiCell*  cell   = &table->header[col];
+    const uiLabel* label  = (uiLabel*)cell->child;
+    const int      length = (int)string_length(label->text);
+
+    widths[col] = length;
+  }
+  // Table contents.
+  for (int row = 0; row < table->rows; ++row) {
+    for (int col = 0; col < table->cols; ++col) {
+      const uiCell* cell = GetCell(table, row, col);
+      if (cell->child) {
+        const uiLabel* label  = (uiLabel*)cell->child;
+        const int      length = (int)string_length(label->text);
+
+        widths[col] = length > widths[col] ? length : widths[col];
+      }
+    }
+  }
+  // Multiply string lengths times glyph width to compute pixel size.
+  for (int col = 0; col < table->cols; ++col) {
+    widths[col] *= g_ui.font->header.glyph_width;
+  }
+
+  // Find the sum of widths.
+  int used_width = 0;
+  for (int col = 0; col < table->cols; ++col) {
+    used_width += widths[col];
+  }
+
+  // Pad if available width is larger than sum of widths.
+  if (used_width < width) {
+    // Divide evenly among columns.
+    // const int extra = width - used_width;
+    //    const int pad   = extra / table->cols;
+    //    const int mod   = extra % table->cols;
+    //    for (int col = 0; col < table->cols; ++col) {
+    //      table->widths[col] += pad + (col < mod ? 1 : 0);
+    //    }
+
+    int extra = width - used_width;
+    while (extra > 0) {
+      // Find smallest column.
+      int smallest = 0;
+      for (int col = 1; col < table->cols; ++col) {
+        if (widths[col] < widths[smallest]) {
+          smallest = col;
+        }
+      }
+      // Pad it and subtract from the budget.
+      widths[smallest] += 1;
+      extra--;
+    }
+  }
+  // Shrink if available width is smaller than the sum of widths.
+  else if (used_width > width) {
+    int deficit = used_width - width;
+    while (deficit > 0) {
+      // Find largest column.
+      int largest = 0;
+      for (int col = 1; col < table->cols; ++col) {
+        if (widths[col] > widths[largest]) {
+          largest = col;
+        }
+      }
+      // Shrink it and subtract from the deficit.
+      widths[largest] -= 1;
+      deficit--;
+    }
+  }
+
+  // Now make room for the scroll bar, if necessary.
+  if (table->flags.vertical_overflow) {
+    const int offset    = ScrollBarWidth / table->cols;
+    const int remainder = ScrollBarWidth % table->cols;
+    for (int col = 0; col < table->cols; ++col) {
+      table->widths[col] -= offset + (col < remainder ? 1 : 0);
+      assert(table->widths[col] >= 0);
+    }
+  }
+}
+
+static void ResizeWidget(uiWidget* widget, int width, int height) {
+  assert(widget);
+
+  widget->rect.width  = width;
+  widget->rect.height = height;
+
+  switch (widget->type) {
+  case uiTypeButton:
+    break;
+  case uiTypeFrame:
+    list_foreach_mut(
+        widget->children, child, { ResizeWidget(child, width, height); });
+    break;
+  case uiTypeLabel:
+    break;
+  case uiTypeTable:
+    ResizeTable((uiTable*)widget, width, height);
+    break;
+  case uiTypeMax:
+    TRAP();
+    break;
+  }
+}
+
+void uiResizeFrame(uiFrame* frame, int width, int height) {
+  assert(frame);
+  ResizeWidget(&frame->widget, width, height);
+}