From c58c46c96cf490a1d585a28560dda138479f00be Mon Sep 17 00:00:00 2001
From: Jaakko Keränen <jaakko.keranen@iki.fi>
Date: Mon, 7 Sep 2020 06:50:34 +0300
Subject: LookupWidget: Improved keyboard navigation

---
 src/ui/listwidget.c   | 18 +++++++++++++++---
 src/ui/listwidget.h   |  2 ++
 src/ui/lookupwidget.c | 38 ++++++++++++++++++++++----------------
 3 files changed, 39 insertions(+), 19 deletions(-)

(limited to 'src/ui')

diff --git a/src/ui/listwidget.c b/src/ui/listwidget.c
index 06689023..3e7203b8 100644
--- a/src/ui/listwidget.c
+++ b/src/ui/listwidget.c
@@ -179,8 +179,20 @@ void scrollOffset_ListWidget(iListWidget *d, int offset) {
     }
 }
 
-static int visCount_ListWidget_(const iListWidget *d) {
-    return iMin(height_Rect(innerBounds_Widget(constAs_Widget(d))) / d->itemHeight + 2,
+void scrollToItem_ListWidget(iListWidget *d, size_t index) {
+    const iRect rect    = innerBounds_Widget(as_Widget(d));
+    int         yTop    = d->itemHeight * index - d->scrollY;
+    int         yBottom = yTop + d->itemHeight;
+    if (yBottom > height_Rect(rect)) {
+        scrollOffset_ListWidget(d, yBottom - height_Rect(rect));
+    }
+    else if (yTop < 0) {
+        scrollOffset_ListWidget(d, yTop);
+    }
+}
+
+int visCount_ListWidget(const iListWidget *d) {
+    return iMin(height_Rect(innerBounds_Widget(constAs_Widget(d))) / d->itemHeight,
                 (int) size_PtrArray(&d->items));
 }
 
@@ -189,7 +201,7 @@ static iRanges visRange_ListWidget_(const iListWidget *d) {
         return (iRanges){ 0, 0 };
     }
     iRanges vis = { d->scrollY / d->itemHeight, 0 };
-    vis.end = iMin(size_PtrArray(&d->items), vis.start + visCount_ListWidget_(d));
+    vis.end = iMin(size_PtrArray(&d->items), vis.start + visCount_ListWidget(d) + 1);
     return vis;
 }
 
diff --git a/src/ui/listwidget.h b/src/ui/listwidget.h
index 72b7dba4..29140c59 100644
--- a/src/ui/listwidget.h
+++ b/src/ui/listwidget.h
@@ -59,6 +59,7 @@ int     itemHeight_ListWidget   (const iListWidget *);
 int     scrollPos_ListWidget    (const iListWidget *);
 
 void    setScrollPos_ListWidget     (iListWidget *, int pos);
+void    scrollToItem_ListWidget     (iListWidget *, size_t index);
 void    scrollOffset_ListWidget     (iListWidget *, int offset);
 void    updateVisible_ListWidget    (iListWidget *);
 void    updateMouseHover_ListWidget (iListWidget *);
@@ -67,6 +68,7 @@ iAnyObject *item_ListWidget         (iListWidget *, size_t index);
 iAnyObject *hoverItem_ListWidget    (iListWidget *);
 
 size_t  numItems_ListWidget (const iListWidget *);
+int visCount_ListWidget(const iListWidget *);
 size_t  itemIndex_ListWidget(const iListWidget *, iInt2 pos);
 const iAnyObject *constItem_ListWidget      (const iListWidget *, size_t index);
 const iAnyObject *constHoverItem_ListWidget (const iListWidget *);
diff --git a/src/ui/lookupwidget.c b/src/ui/lookupwidget.c
index fbb5d365..c1c52708 100644
--- a/src/ui/lookupwidget.c
+++ b/src/ui/lookupwidget.c
@@ -372,9 +372,25 @@ static void setCursor_LookupWidget_(iLookupWidget *d, size_t index) {
             item->listItem.isSelected = iTrue;
             invalidateItem_ListWidget(d->list, d->cursor);
         }
+        scrollToItem_ListWidget(d->list, d->cursor);
     }
 }
 
+static iBool moveCursor_LookupWidget_(iLookupWidget *d, int delta) {
+    const int dir  = iSign(delta);
+    size_t    cur  = d->cursor;
+    size_t    good = cur;
+    while (delta && ((dir < 0 && cur > 0) || (dir > 0 && cur < numItems_ListWidget(d->list) - 1))) {
+        cur += dir;
+        if (!item_LookupWidget_(d, cur)->listItem.isSeparator) {
+            delta -= dir;
+            good = cur;
+        }
+    }
+    setCursor_LookupWidget_(d, good);
+    return delta == 0;
+}
+
 static iBool processEvent_LookupWidget_(iLookupWidget *d, const SDL_Event *ev) {
     iWidget *w = as_Widget(d);
     const char *cmd = command_UserEvent(ev);
@@ -431,29 +447,19 @@ static iBool processEvent_LookupWidget_(iLookupWidget *d, const SDL_Event *ev) {
                     setFocus_Widget(url);
                     return iTrue;
                 case SDLK_UP:
-                    for (;;) {
-                        if (d->cursor == 0) {
-                            setCursor_LookupWidget_(d, iInvalidPos);
-                            setFocus_Widget(url);
-                            break;
-                        }
-                        setCursor_LookupWidget_(d, d->cursor - 1);
-                        if (!item_LookupWidget_(d, d->cursor)->listItem.isSeparator) {
-                            break;
-                        }
+                    if (!moveCursor_LookupWidget_(d, -1)) {
+                        setCursor_LookupWidget_(d, iInvalidPos);
+                        setFocus_Widget(url);
                     }
                     return iTrue;
                 case SDLK_DOWN:
-                    while (d->cursor < numItems_ListWidget(d->list) - 1) {
-                        setCursor_LookupWidget_(d, d->cursor + 1);
-                        if (!item_LookupWidget_(d, d->cursor)->listItem.isSeparator) {
-                            break;
-                        }
-                    }
+                    moveCursor_LookupWidget_(d, +1);
                     return iTrue;
                 case SDLK_PAGEUP:
+                    moveCursor_LookupWidget_(d, -visCount_ListWidget(d->list) + 1);
                     return iTrue;
                 case SDLK_PAGEDOWN:
+                    moveCursor_LookupWidget_(d, visCount_ListWidget(d->list) - 1);
                     return iTrue;
                 case SDLK_HOME:
                     setCursor_LookupWidget_(d, 1);
-- 
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