bc11bd8d5f
git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11525 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
88 lines
2.4 KiB
C++
88 lines
2.4 KiB
C++
//
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// "$Id$"
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//
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// Scrolling routines for the Fast Light Tool Kit (FLTK).
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//
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// Copyright 1998-2016 by Bill Spitzak and others.
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//
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// This library is free software. Distribution and use rights are outlined in
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// the file "COPYING" which should have been included with this file. If this
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// file is missing or damaged, see the license at:
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//
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// http://www.fltk.org/COPYING.php
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//
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// Please report all bugs and problems on the following page:
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//
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// http://www.fltk.org/str.php
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//
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// Drawing function to move the contents of a rectangle. This is passed
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// a "callback" which is called to draw rectangular areas that are moved
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// into the drawing area.
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#include <FL/Fl_Window_Driver.H>
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// scroll a rectangle and redraw the newly exposed portions:
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/**
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Scroll a rectangle and draw the newly exposed portions.
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\param[in] X,Y position of top-left of rectangle
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\param[in] W,H size of rectangle
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\param[in] dx,dy pixel offsets for shifting rectangle
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\param[in] draw_area callback function to draw rectangular areas
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\param[in] data pointer to user data for callback
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The contents of the rectangular area is first shifted by \p dx
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and \p dy pixels. The \p draw_area callback is then called for
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every newly exposed rectangular area.
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*/
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void fl_scroll(int X, int Y, int W, int H, int dx, int dy,
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void (*draw_area)(void*, int,int,int,int), void* data)
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{
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if (!dx && !dy) return;
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if (dx <= -W || dx >= W || dy <= -H || dy >= H) {
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// no intersection of old an new scroll
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draw_area(data,X,Y,W,H);
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return;
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}
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int src_x, src_w, dest_x, clip_x, clip_w;
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if (dx > 0) {
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src_x = X;
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dest_x = X+dx;
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src_w = W-dx;
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clip_x = X;
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clip_w = dx;
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} else {
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src_x = X-dx;
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dest_x = X;
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src_w = W+dx;
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clip_x = X+src_w;
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clip_w = W-src_w;
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}
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int src_y, src_h, dest_y, clip_y, clip_h;
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if (dy > 0) {
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src_y = Y;
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dest_y = Y+dy;
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src_h = H-dy;
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clip_y = Y;
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clip_h = dy;
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} else {
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src_y = Y-dy;
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dest_y = Y;
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src_h = H+dy;
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clip_y = Y+src_h;
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clip_h = H-src_h;
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}
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int retval = Fl_Window::current()->driver()->scroll(src_x, src_y, src_w, src_h,
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dest_x, dest_y, draw_area, data);
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if (retval) {
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draw_area(data,X,Y,W,H);
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return;
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}
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if (dx) draw_area(data, clip_x, dest_y, clip_w, src_h);
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if (dy) draw_area(data, X, clip_y, W, clip_h);
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}
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//
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// End of "$Id$".
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//
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