changed inner scroll a bit

src/desktoplib/terminal/ui/InnerScroll.cpp

@@ -5,53 +5,64 @@
 namespace ckitty::terminal {
 
     InnerScroll::InnerScroll(pos p, int w, int h, Content& c)
-        : position(p), width(w), height(h), _content(c) {
+        : position(p), width(w), height(h), rowY(0), scrollY(0), _content(c) {
     }
 
     void InnerScroll::scroll(int delta) {
-        int maxScroll = std::max(0, _content.getTotalHeight() - height);
+        int totalH = _content.getTotalHeight();
-        scrollY = std::clamp(scrollY + delta, 0, maxScroll);
+        int viewH = height;
+        if (totalH == 0) return;
+
+        // 1. Update and clamp the cursor position within absolute content bounds
+        rowY = std::clamp(rowY + delta, 0, std::max(0, totalH - 1));
+
+        // 2. Adjust scrollY to keep rowY visible
+        // Case A: Cursor moved above the top of the viewport
+        if (rowY < scrollY) {
+            scrollY = rowY;
+        }
+        // Case B: Cursor moved below the bottom of the viewport
+        else if (rowY >= scrollY + viewH) {
+            scrollY = rowY - viewH + 1;
+        }
+
+        // 3. Final safety clamp for scrollY
+        int maxScroll = std::max(0, totalH - viewH);
+        scrollY = std::clamp(scrollY, 0, maxScroll);
     }
 
     void InnerScroll::render(Terminal& t) const {
         int totalH = _content.getTotalHeight();
         int viewH = height;
         int contentWidth = width - 1; // Last column reserved for scrollbar
+        int scrollX = position.x + width - 1;
 
-        // 1. Render the Content Viewport
+        // draw content
-        // We only ask content to draw what fits in our height
         int start = scrollY;
         int end = std::min(totalH, scrollY + viewH);
-
         _content.render(t, position, pos(contentWidth, height), { start, end });
 
-        // 2. Clear empty space if content is shorter than viewport
+        // 3. Render Scrollbar Track First
-        if (end - start < viewH) {
+        t << style::RESET << trackColor;
-            for (int y = (end - start); y < viewH; ++y) {
-                t << pos{ position.x, position.y + y }
-                << std::string(std::size_t(contentWidth), ' ');
-            }
-        }
-
-        // 3. Render Scrollbar Track
-        int scrollX = position.x + width - 1;
-        t << trackColor;
         for (int y = 0; y < viewH; ++y) {
-            t << pos{ scrollX, position.y + y } << "░";
+            t << pos(scrollX, position.y + y) << "░";
         }
 
-        // 4. Render Scrollbar Thumb
+        // 4. Render Scrollbar Thumb Over the Track
         if (totalH > viewH) {
             // Calculate thumb height (proportional to visibility)
             int thumbH = std::max(1, (viewH * viewH) / totalH);
 
-            // Calculate thumb position
+            // Calculate thumb position safely
             float scrollPercent = float(scrollY) / float(totalH - viewH);
             int thumbPos = int(scrollPercent * float(viewH - thumbH));
 
+            // Clamp thumbPos to ensure it stays within the track bounds
+            thumbPos = std::clamp(thumbPos, 0, viewH - thumbH);
+
             t << thumbColor;
             for (int y = 0; y < thumbH; ++y) {
-                t << pos{ scrollX, position.y + thumbPos + y } << "█";
+                t << pos(scrollX, position.y + thumbPos + y) << "█";
             }
         }
 

src/desktoplib/terminal/ui/InnerScroll.hpp

@@ -12,7 +12,7 @@ namespace ckitty::terminal {
 
         pos position;
         int width, height;
-        int scrollY = 0; // The top-most visible row of the content
+        int rowY, scrollY;
 
         // Styling
         color trackColor = color::B_BLACK;