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https://github.com/juce-framework/JUCE.git
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ad5a755b10
For some transforms, the program could get stuck in the following loop: - The content component emits a resized/moved notification, leading to the initial call to Viewport::updateVisibleArea. - New positions are computed for the viewport scrollbars, and scrollbar listeners are notified synchronously that the scrollbars have been updated. - The viewport itself listens to the scrollbars, so it receives a notification and updates the position of the content component. - The scrollbar position (quantised to an integer) resolves to a component position (also quantised to an integer) that differs from the existing position, so the new position is applied. - The viewport now attempts to set the scrollbars to the correct position in response, and notifies listeners that the scrollbars have moved... Normally, the recursion would exit at the point where the component position is set to its current position. If we're unlucky, though, converting from view pos to scrollbar pos, then scrollbar pos back to view pos may result in a view pos that differs from the original value. This fix adds a new exit condition from the recursion. On receiving a scrollbar move notification, we check whether the scrollbar position computed from the current view position matches the incoming scrollbar position. If it does, there's no need to compute and apply a new view position from the incoming scrollbar position.
384 lines
17 KiB
C++
384 lines
17 KiB
C++
/*
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==============================================================================
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This file is part of the JUCE framework.
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Copyright (c) Raw Material Software Limited
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JUCE is an open source framework subject to commercial or open source
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licensing.
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By downloading, installing, or using the JUCE framework, or combining the
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JUCE framework with any other source code, object code, content or any other
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copyrightable work, you agree to the terms of the JUCE End User Licence
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Agreement, and all incorporated terms including the JUCE Privacy Policy and
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the JUCE Website Terms of Service, as applicable, which will bind you. If you
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do not agree to the terms of these agreements, we will not license the JUCE
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framework to you, and you must discontinue the installation or download
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process and cease use of the JUCE framework.
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JUCE End User Licence Agreement: https://juce.com/legal/juce-8-licence/
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JUCE Privacy Policy: https://juce.com/juce-privacy-policy
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JUCE Website Terms of Service: https://juce.com/juce-website-terms-of-service/
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Or:
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You may also use this code under the terms of the AGPLv3:
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https://www.gnu.org/licenses/agpl-3.0.en.html
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THE JUCE FRAMEWORK IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL
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WARRANTIES, WHETHER EXPRESSED OR IMPLIED, INCLUDING WARRANTY OF
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MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED.
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==============================================================================
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*/
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namespace juce
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{
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//==============================================================================
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/**
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A Viewport is used to contain a larger child component, and allows the child
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to be automatically scrolled around.
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To use a Viewport, just create one and set the component that goes inside it
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using the setViewedComponent() method. When the child component changes size,
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the Viewport will adjust its scrollbars accordingly.
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A subclass of the viewport can be created which will receive calls to its
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visibleAreaChanged() method when the subcomponent changes position or size.
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@tags{GUI}
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*/
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class JUCE_API Viewport : public Component,
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private ComponentListener,
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private ScrollBar::Listener
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{
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public:
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//==============================================================================
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/** Creates a Viewport.
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The viewport is initially empty - use the setViewedComponent() method to
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add a child component for it to manage.
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*/
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explicit Viewport (const String& componentName = String());
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/** Destructor. */
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~Viewport() override;
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//==============================================================================
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/** Sets the component that this viewport will contain and scroll around.
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This will add the given component to this Viewport and position it at (0, 0).
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(Don't add or remove any child components directly using the normal
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Component::addChildComponent() methods).
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@param newViewedComponent the component to add to this viewport, or null to remove
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the current component.
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@param deleteComponentWhenNoLongerNeeded if true, the component will be deleted
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automatically when the viewport is deleted or when a different
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component is added. If false, the caller must manage the lifetime
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of the component
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@see getViewedComponent
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*/
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void setViewedComponent (Component* newViewedComponent,
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bool deleteComponentWhenNoLongerNeeded = true);
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/** Returns the component that's currently being used inside the Viewport.
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@see setViewedComponent
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*/
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Component* getViewedComponent() const noexcept { return contentComp.get(); }
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//==============================================================================
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/** Changes the position of the viewed component.
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The inner component will be moved so that the pixel at the top left of
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the viewport will be the pixel at position (xPixelsOffset, yPixelsOffset)
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within the inner component.
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This will update the scrollbars and might cause a call to visibleAreaChanged().
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@see getViewPositionX, getViewPositionY, setViewPositionProportionately
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*/
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void setViewPosition (int xPixelsOffset, int yPixelsOffset);
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/** Changes the position of the viewed component.
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The inner component will be moved so that the pixel at the top left of
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the viewport will be the pixel at the specified coordinates within the
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inner component.
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This will update the scrollbars and might cause a call to visibleAreaChanged().
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@see getViewPositionX, getViewPositionY, setViewPositionProportionately
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*/
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void setViewPosition (Point<int> newPosition);
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/** Changes the view position as a proportion of the distance it can move.
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The values here are from 0.0 to 1.0 - where (0, 0) would put the
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visible area in the top-left, and (1, 1) would put it as far down and
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to the right as it's possible to go whilst keeping the child component
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on-screen.
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*/
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void setViewPositionProportionately (double proportionX, double proportionY);
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/** If the specified position is at the edges of the viewport, this method scrolls
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the viewport to bring that position nearer to the centre.
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Call this if you're dragging an object inside a viewport and want to make it scroll
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when the user approaches an edge. You might also find Component::beginDragAutoRepeat()
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useful when auto-scrolling.
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@param mouseX the x position, relative to the Viewport's top-left
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@param mouseY the y position, relative to the Viewport's top-left
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@param distanceFromEdge specifies how close to an edge the position needs to be
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before the viewport should scroll in that direction
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@param maximumSpeed the maximum number of pixels that the viewport is allowed
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to scroll by.
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@returns true if the viewport was scrolled
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*/
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bool autoScroll (int mouseX, int mouseY, int distanceFromEdge, int maximumSpeed);
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/** Returns the position within the child component of the top-left of its visible area. */
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Point<int> getViewPosition() const noexcept { return lastVisibleArea.getPosition(); }
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/** Returns the visible area of the child component, relative to its top-left */
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Rectangle<int> getViewArea() const noexcept { return lastVisibleArea; }
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/** Returns the position within the child component of the top-left of its visible area.
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@see getViewWidth, setViewPosition
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*/
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int getViewPositionX() const noexcept { return lastVisibleArea.getX(); }
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/** Returns the position within the child component of the top-left of its visible area.
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@see getViewHeight, setViewPosition
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*/
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int getViewPositionY() const noexcept { return lastVisibleArea.getY(); }
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/** Returns the width of the visible area of the child component.
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This may be less than the width of this Viewport if there's a vertical scrollbar
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or if the child component is itself smaller.
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*/
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int getViewWidth() const noexcept { return lastVisibleArea.getWidth(); }
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/** Returns the height of the visible area of the child component.
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This may be less than the height of this Viewport if there's a horizontal scrollbar
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or if the child component is itself smaller.
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*/
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int getViewHeight() const noexcept { return lastVisibleArea.getHeight(); }
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/** Returns the width available within this component for the contents.
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This will be the width of the viewport component minus the width of a
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vertical scrollbar (if visible).
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*/
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int getMaximumVisibleWidth() const;
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/** Returns the height available within this component for the contents.
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This will be the height of the viewport component minus the space taken up
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by a horizontal scrollbar (if visible).
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*/
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int getMaximumVisibleHeight() const;
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//==============================================================================
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/** Callback method that is called when the visible area changes.
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This will be called when the visible area is moved either be scrolling or
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by calls to setViewPosition(), etc.
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*/
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virtual void visibleAreaChanged (const Rectangle<int>& newVisibleArea);
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/** Callback method that is called when the viewed component is added, removed or swapped. */
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virtual void viewedComponentChanged (Component* newComponent);
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//==============================================================================
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/** Turns scrollbars on or off.
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If set to false, the scrollbars won't ever appear. When true (the default)
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they will appear only when needed.
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The allowVerticalScrollingWithoutScrollbar parameters allow you to enable
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mouse-wheel scrolling even when there the scrollbars are hidden. When the
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scrollbars are visible, these parameters are ignored.
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*/
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void setScrollBarsShown (bool showVerticalScrollbarIfNeeded,
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bool showHorizontalScrollbarIfNeeded,
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bool allowVerticalScrollingWithoutScrollbar = false,
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bool allowHorizontalScrollingWithoutScrollbar = false);
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/** Changes where the scroll bars are positioned
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If verticalScrollbarOnRight is set to true, then the vertical scrollbar will
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appear on the right side of the view port's content (this is the default),
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otherwise it will be on the left side of the content.
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If horizontalScrollbarAtBottom is set to true, then the horizontal scrollbar
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will appear at the bottom of the view port's content (this is the default),
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otherwise it will be at the top.
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*/
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void setScrollBarPosition (bool verticalScrollbarOnRight,
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bool horizontalScrollbarAtBottom);
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/** True if the vertical scrollbar will appear on the right side of the content */
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bool isVerticalScrollbarOnTheRight() const noexcept { return vScrollbarRight; }
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/** True if the horizontal scrollbar will appear at the bottom of the content */
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bool isHorizontalScrollbarAtBottom() const noexcept { return hScrollbarBottom; }
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/** True if the vertical scrollbar is enabled.
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@see setScrollBarsShown
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*/
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bool isVerticalScrollBarShown() const noexcept { return showVScrollbar; }
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/** True if the horizontal scrollbar is enabled.
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@see setScrollBarsShown
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*/
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bool isHorizontalScrollBarShown() const noexcept { return showHScrollbar; }
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/** Changes the width of the scrollbars.
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If this isn't specified, the default width from the LookAndFeel class will be used.
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@see LookAndFeel::getDefaultScrollbarWidth
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*/
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void setScrollBarThickness (int thickness);
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/** Returns the thickness of the scrollbars.
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@see setScrollBarThickness
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*/
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int getScrollBarThickness() const;
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/** Changes the distance that a single-step click on a scrollbar button
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will move the viewport.
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*/
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void setSingleStepSizes (int stepX, int stepY);
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/** Returns a reference to the scrollbar component being used.
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Handy if you need to customise the bar somehow.
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*/
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ScrollBar& getVerticalScrollBar() noexcept { return *verticalScrollBar; }
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/** Returns a reference to the scrollbar component being used.
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Handy if you need to customise the bar somehow.
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*/
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ScrollBar& getHorizontalScrollBar() noexcept { return *horizontalScrollBar; }
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/** Re-instantiates the scrollbars, which is only really useful if you've overridden createScrollBarComponent(). */
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void recreateScrollbars();
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/** True if there's any off-screen content that could be scrolled vertically,
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or false if everything is currently visible.
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*/
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bool canScrollVertically() const noexcept;
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/** True if there's any off-screen content that could be scrolled horizontally,
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or false if everything is currently visible.
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*/
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bool canScrollHorizontally() const noexcept;
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/** Enables or disables drag-to-scroll functionality for mouse sources in the viewport.
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If your viewport contains a Component that you don't want to receive mouse events when the
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user is drag-scrolling, you can disable this with the Component::setViewportIgnoreDragFlag()
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method.
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*/
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[[deprecated ("Use setScrollOnDragMode instead.")]]
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void setScrollOnDragEnabled (bool shouldScrollOnDrag)
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{
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setScrollOnDragMode (shouldScrollOnDrag ? ScrollOnDragMode::all : ScrollOnDragMode::never);
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}
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/** Returns true if drag-to-scroll functionality is enabled for mouse input sources. */
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[[deprecated ("Use getScrollOnDragMode instead.")]]
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bool isScrollOnDragEnabled() const noexcept { return getScrollOnDragMode() == ScrollOnDragMode::all; }
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enum class ScrollOnDragMode
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{
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never, /**< Dragging will never scroll the viewport. */
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nonHover, /**< Dragging will only scroll the viewport if the input source cannot hover. */
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all /**< Dragging will always scroll the viewport. */
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};
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/** Sets the current scroll-on-drag mode. The default is ScrollOnDragMode::nonHover.
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If your viewport contains a Component that you don't want to receive mouse events when the
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user is drag-scrolling, you can disable this with the Component::setViewportIgnoreDragFlag()
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method.
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*/
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void setScrollOnDragMode (ScrollOnDragMode scrollOnDragMode);
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/** Returns the current scroll-on-drag mode. */
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ScrollOnDragMode getScrollOnDragMode() const { return scrollOnDragMode; }
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/** Returns true if the user is currently dragging-to-scroll.
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@see setScrollOnDragEnabled
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*/
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bool isCurrentlyScrollingOnDrag() const noexcept;
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//==============================================================================
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/** @internal */
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void resized() override;
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/** @internal */
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void scrollBarMoved (ScrollBar*, double newRangeStart) override;
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/** @internal */
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void mouseWheelMove (const MouseEvent&, const MouseWheelDetails&) override;
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/** @internal */
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void mouseDown (const MouseEvent& e) override;
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/** @internal */
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bool keyPressed (const KeyPress&) override;
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/** @internal */
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void componentMovedOrResized (Component&, bool wasMoved, bool wasResized) override;
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/** @internal */
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void lookAndFeelChanged() override;
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/** @internal */
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bool useMouseWheelMoveIfNeeded (const MouseEvent&, const MouseWheelDetails&);
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/** @internal */
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static bool respondsToKey (const KeyPress&);
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protected:
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//==============================================================================
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/** Creates the Scrollbar components that will be added to the Viewport.
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Subclasses can override this if they need to customise the scrollbars in some way.
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*/
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virtual ScrollBar* createScrollBarComponent (bool isVertical);
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private:
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//==============================================================================
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class AccessibilityIgnoredComponent : public Component
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{
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public:
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std::unique_ptr<AccessibilityHandler> createAccessibilityHandler() override
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{
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return createIgnoredAccessibilityHandler (*this);
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}
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};
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std::unique_ptr<ScrollBar> verticalScrollBar, horizontalScrollBar;
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AccessibilityIgnoredComponent contentHolder;
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WeakReference<Component> contentComp;
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Rectangle<int> lastVisibleArea;
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int scrollBarThickness = 0;
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int singleStepX = 16, singleStepY = 16;
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ScrollOnDragMode scrollOnDragMode = ScrollOnDragMode::nonHover;
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bool showHScrollbar = true, showVScrollbar = true, deleteContent = true;
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bool customScrollBarThickness = false;
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bool allowScrollingWithoutScrollbarV = false, allowScrollingWithoutScrollbarH = false;
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bool vScrollbarRight = true, hScrollbarBottom = true;
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struct DragToScrollListener;
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std::unique_ptr<DragToScrollListener> dragToScrollListener;
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Point<int> viewportPosToCompPos (Point<int>) const;
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Rectangle<int> getContentBounds() const;
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void updateVisibleArea();
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void deleteOrRemoveContentComp();
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Viewport)
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};
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} // namespace juce
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