From 92978a10576d52a0f6c9983d3b6afae7c40eff40 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Thu, 12 Mar 2026 15:29:23 -0700
Subject: Support scrolling by dragging scrollbars

---
 src/widget/widget.h | 49 +++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

(limited to 'src/widget/widget.h')

diff --git a/src/widget/widget.h b/src/widget/widget.h
index 63f3d94..db11164 100644
--- a/src/widget/widget.h
+++ b/src/widget/widget.h
@@ -16,39 +16,42 @@ typedef struct uiWidget {
   Widget_list  children;
 } uiWidget;
 
-/// Button.
 typedef struct uiButton {
   uiWidget widget;
   string   text;
 } uiButton;
 
-/// Frame.
 typedef struct uiFrame {
   uiWidget widget;
 } uiFrame;
 
-/// Label.
 typedef struct uiLabel {
   uiWidget widget;
   string   text;
 } uiLabel;
 
-/// Table cell.
+typedef struct uiScrollbar {
+  int width;
+  int height;        // Total height: handle plus scrollable area.
+  int handle_height; // Height of the scroll handle.
+  int handle_y;      // Starting y-coordinate of the handle.
+} uiScrollbar;
+
 typedef struct uiCell {
   string text;
 } uiCell;
 
-/// Table.
 typedef struct uiTable {
-  uiWidget widget;
-  int      rows;
-  int      cols;
-  int      height;           // Height in pixels.
-  int*     widths;           // Width, in pixels, for each column.
-  uiCell*  header;           // If non-null, row of 'cols' header cells.
-  uiCell** cells;            // Array of 'rows' rows, each of 'cols' cells.
-  int      offset;           // Offset into the rows of the table. Units: rows.
-  int      num_visible_rows; // The number of rows that are visible at once.
+  uiWidget    widget;
+  int         rows;
+  int         cols;
+  int         height; // Height in pixels.
+  int*        widths; // Width, in pixels, for each column.
+  uiCell*     header; // If non-null, row of 'cols' header cells.
+  uiCell**    cells;  // Array of 'rows' rows, each of 'cols' cells.
+  int         offset; // Offset into the rows of the table. Units: rows.
+  int         num_visible_rows; // The number of rows that are visible at once.
+  uiScrollbar scrollbar;
   struct {
     bool vertical_overflow : 1; // True if contents overflow vertically.
   } flags;
@@ -56,14 +59,24 @@ typedef struct uiTable {
 
 void DestroyWidget(uiWidget** ppWidget);
 
-const uiCell* GetCell(const uiTable* table, int row, int col);
-uiCell*       GetCellMut(uiTable* table, int row, int col);
-uiCell**      GetLastRow(uiTable* table);
+/// Set the scrollbar handle's y-coordinate, which is clipped to the scrollbar's
+/// rectangle.
+///
+/// Return the handle's y-coordinate after clipping.
+int ScrollbarScroll(uiScrollbar*, int y);
 
-#define UI_NEW(TYPE) (TYPE*)uiAlloc(1, sizeof(TYPE))
+const uiCell* TableGetCell(const uiTable*, int row, int col);
+uiCell*       TableGetCellMut(uiTable*, int row, int col);
+uiCell**      TableGetLastRow(uiTable*);
+void          SyncScrollbarToTable(uiTable*);
+void          SyncTableToScrollbar(uiTable*);
+
+static inline int Min(int a, int b) { return a < b ? a : b; }
+static inline int Max(int a, int b) { return a > b ? a : b; }
 
 static inline void* uiAlloc(size_t count, size_t size) {
   void* mem = calloc(count, size);
   ASSERT(mem);
   return mem;
 }
+#define UI_NEW(TYPE) (TYPE*)uiAlloc(1, sizeof(TYPE))
-- 
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