add adjustable minimum scroller size for the scrollbar

steinbergmedia · Oct 23, 2024 · b55ef07 · b55ef07
1 parent 2a6086e
commit b55ef07
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Showing 5 changed files with 37 additions and 4 deletions.
diff --git a/vstgui/lib/controls/cscrollbar.cpp b/vstgui/lib/controls/cscrollbar.cpp
@@ -91,8 +91,8 @@ void CScrollbar::calculateScrollerLength ()
 			factor = 0;
 		newScrollerLength = (CCoord) (getViewSize ().getHeight () * factor);
 	}
-	if (newScrollerLength < 8. && newScrollerLength > 0.)
-		newScrollerLength = 8.;
+	if (newScrollerLength < minScrollerLenght && newScrollerLength > 0.)
+		newScrollerLength = minScrollerLenght;
 	if (newScrollerLength != scrollerLength)
 	{
 		scrollerLength = newScrollerLength;
@@ -175,6 +175,17 @@ void CScrollbar::setOverlayStyle (bool state)
 	}
 }
 
+//------------------------------------------------------------------------
+void CScrollbar::setMinScrollerLength (CCoord length)
+{
+	if (minScrollerLenght != length)
+	{
+		minScrollerLenght = length;
+		calculateScrollerLength ();
+		setDirty ();
+	}
+}
+
 //-----------------------------------------------------------------------------
 CMouseEventResult CScrollbar::onMouseEntered (CPoint& where, const CButtonState& buttons)
 {

diff --git a/vstgui/lib/controls/cscrollbar.h b/vstgui/lib/controls/cscrollbar.h
@@ -46,7 +46,10 @@ class CScrollbar : public CControl
 
 	bool getOverlayStyle () const { return overlayStyle; }
 	virtual void setOverlayStyle (bool state);
-
+
+	void setMinScrollerLength (CCoord length);
+	CCoord getMinScrollerLength () const { return minScrollerLenght; }
+
 	virtual void onVisualChange ();
 	CRect getScrollerRect ();
 	//@}
@@ -81,7 +84,8 @@ class CScrollbar : public CControl
 
 	float stepValue;
 	CCoord scrollerLength;
-
+	CCoord minScrollerLenght {8.0};
+
 	CColor frameColor;
 	CColor scrollerColor;
 	CColor backgroundColor;

diff --git a/vstgui/standalone/examples/standalone/resource/test.uidesc b/vstgui/standalone/examples/standalone/resource/test.uidesc
@@ -868,6 +868,7 @@
 									"overlay-scrollbars": "false",
 									"scrollbar-background-color": "~ TransparentCColor",
 									"scrollbar-frame-color": "~ TransparentCColor",
+									"scrollbar-min-scroller-size": "8",
 									"scrollbar-scroller-color": "~ WhiteCColor",
 									"scrollbar-width": "12",
 									"size": "110, 140",
@@ -963,6 +964,7 @@
 									"overlay-scrollbars": "false",
 									"scrollbar-background-color": "~ TransparentCColor",
 									"scrollbar-frame-color": "~ TransparentCColor",
+									"scrollbar-min-scroller-size": "18",
 									"scrollbar-scroller-color": "~ WhiteCColor",
 									"scrollbar-width": "12",
 									"size": "270, 140",

diff --git a/vstgui/uidescription/detail/uiviewcreatorattributes.h b/vstgui/uidescription/detail/uiviewcreatorattributes.h
@@ -122,6 +122,7 @@ static const std::string kAttrScrollbarBackgroundColor = "scrollbar-background-c
 static const std::string kAttrScrollbarFrameColor = "scrollbar-frame-color";
 static const std::string kAttrScrollbarScrollerColor = "scrollbar-scroller-color";
 static const std::string kAttrScrollbarWidth = "scrollbar-width";
+static const std::string kAttrMinScrollerSize = "scrollbar-min-scroller-size";
 
 //-----------------------------------------------------------------------------
 // CControlCreator attributes

diff --git a/vstgui/uidescription/viewcreator/scrollviewcreator.cpp b/vstgui/uidescription/viewcreator/scrollviewcreator.cpp
@@ -111,6 +111,13 @@ bool ScrollViewCreator::apply (CView* view, const UIAttributes& attributes,
 	CCoord width;
 	if (attributes.getDoubleAttribute (kAttrScrollbarWidth, width))
 		scrollView->setScrollbarWidth (width);
+	if (attributes.getDoubleAttribute (kAttrMinScrollerSize, width))
+	{
+		if (vscrollbar)
+			vscrollbar->setMinScrollerLength (width);
+		if (hscrollbar)
+			hscrollbar->setMinScrollerLength (width);
+	}
 	return true;
 }
 
@@ -127,6 +134,7 @@ bool ScrollViewCreator::getAttributeNames (StringList& attributeNames) const
 	attributeNames.emplace_back (kAttrAutoDragScrolling);
 	attributeNames.emplace_back (kAttrOverlayScrollbars);
 	attributeNames.emplace_back (kAttrScrollbarWidth);
+	attributeNames.emplace_back (kAttrMinScrollerSize);
 	attributeNames.emplace_back (kAttrBordered);
 	attributeNames.emplace_back (kAttrFollowFocusView);
 	return true;
@@ -155,6 +163,8 @@ auto ScrollViewCreator::getAttributeType (const string& attributeName) const ->
 		return kBooleanType;
 	if (attributeName == kAttrScrollbarWidth)
 		return kIntegerType;
+	if (attributeName == kAttrMinScrollerSize)
+		return kIntegerType;
 	if (attributeName == kAttrBordered)
 		return kBooleanType;
 	if (attributeName == kAttrFollowFocusView)
@@ -199,6 +209,11 @@ bool ScrollViewCreator::getAttributeValue (CView* view, const string& attributeN
 			colorToString (scrollbar->getScrollerColor (), stringValue, desc);
 			return true;
 		}
+		if (attributeName == kAttrMinScrollerSize)
+		{
+			stringValue = UIAttributes::doubleToString (scrollbar->getMinScrollerLength ());
+			return true;
+		}
 	}
 	if (attributeName == kAttrHorizontalScrollbar)
 	{