71 lines
2.3 KiB
HTML
71 lines
2.3 KiB
HTML
<html>
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<body>
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<hr break>
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<h2><a name="Fl_Overlay_Window">class Fl_Overlay_Window</a></h2>
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<hr>
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<h3>Class Hierarchy</h3>
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<ul><pre>
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<a href="#Fl_Double_Window">Fl_Double_Window</a>
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+----<b>Fl_Overlay_Window</b>
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</pre></ul>
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<h3>Include Files</h3>
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<ul><pre>
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#include <FL/Fl_Overlay_Window.H>
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</pre></ul>
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<h3>Description</h3>
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This window provides double buffering and also the ability to draw the
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"overlay" which is another picture placed on top of the main image.
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The overlay is designed to be a rapidly-changing but simple graphic
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such as a mouse selection box. <tt>Fl_Overlay_Window</tt> uses the
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overlay planes provided by your graphics hardware if they are available.
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<p>If no hardware support is found the overlay is simulated by drawing
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directly into the on-screen copy of the double-buffered window, and
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"erased" by copying the backbuffer over it again. This means the
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overlay will blink if you change the image in the window.
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<h3>Methods</h3>
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<ul>
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<li><a href="#Fl_Overlay_Window.Fl_Overlay_Window">Fl_Overlay_Window</a>
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<li><a href="#Fl_Overlay_Window.~Fl_Overlay_Window">~Fl_Overlay_Window</a>
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<li><a href="#Fl_Overlay_Window.draw_overlay">draw_overlay</a>
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<li><a href="#Fl_Overlay_Window.redraw_overlay">redraw_overlay</a>
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</ul>
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<h4><a name="Fl_Overlay_Window.Fl_Overlay_Window">Fl_Overlay_Window::Fl_Overlay_Window(int x, int y, int w, int h, const char *label = 0)</a></h4>
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Creates a new <tt>Fl_Overlay_Window</tt> widget using the given position, size, and
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label (title) string.
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<h4><a name="Fl_Overlay_Window.~Fl_Overlay_Window">virtual Fl_Overlay_Window::~Fl_Overlay_Window()</a></h4>
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Destroys the window and all child widgets.
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<h4><a name="Fl_Overlay_Window.">virtual void Fl_Overlay_Window::draw_overlay() = 0</a></h4>
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You must subclass <tt>Fl_Overlay_Window</tt> and provide this method. It is
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just like a <tt>draw()</tt> method, except it draws the overlay. The overlay
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will have already been "cleared" when this is called. You can use any
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of the routines described in <a href="#Drawing"><FL/fl_draw.H></a>.
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<h4><a name="Fl_Overlay_Window.">void Fl_Overlay_Window::redraw_overlay()</a></h4>
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Call this to indicate that the overlay data has changed and needs to
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be redrawn. The overlay will be clear until the first time this is
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called, so if you want an initial display you must call this after
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calling <tt>show()</tt>.
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</body>
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</html>
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