All Databases Inside Mac - Basic Toolbox

DragGrayRgn

Drag outline of a region as mouse moves

#include <Windows.h> Window Manager

long DragGrayRgn(theRgn, startPt, limitRect, slopRect, axis, actionProc );

RgnHandle theRgn ; the Region to drag

Point startPt ; control point (mouse position), in local coordinates

Rect *limitRect ; allowed destination area

Rect *slopRect ; allowed mousing area (e.g., size of window)

short axis ; 0=none, 1=horizontal only, 2=vertical only

ProcPtr actionProc ; NIL=let the system handle it

returns hiword=vertical distance moved; low=horiz dist

0x80008000 means released outside of slopRect

DragGrayRgn moves a dotted-line outline of a region, tracking the mouse as

it moves, and retaining control until the mouse is released. It provides means

to limit the axis of motion and the area within which the region may be moved.

theRgn is the handle of a region to be dragged.

startPt is a Point, expressed in coordinates local to the current GrafPort; it

is typically the position of a mouseDown event that is within the

bounds of the region theRgn .

limitRect is the address of an 8-byte Rect structure, expressed in local

coordinates. It sets the boundary within which the region will be

visible as the mouse is dragged. The mouse-pinned point within

theRgn will not be allowed outside of this area.

slopRect is the address of a Rect, in local coordinates, enclosing limitRect . It

sets an outer limit for dragging. When the mouse-pinned point

moves outside of this area, the outlined region will not be displayed.

If the button is released outside of this area, the return value is

0x80008000, and it means the user wanted to abort the drag

operation.

axis lets you limit the region's motion to horizontal or vertical only. It

is one of:

noConstraint (0) motion allowed in all directions

hAxisOnly (1) horizontal motion only

vAxisOnly (2) vertical motion only

actionProc is the address of a procedure that will be called repeatedly as the

mouse is tracked. A value of NIL specifies to let DragGrayRgn keep

control until the mouse is released.

Returns: a 32-bit long integer, defined as two 16-bit words indicating the

distance moved from startPt . The return value may be cast as a

Point; it is broken up as follows:

high word The vertical distance moved

low word The horizontal distance moved

A return value of -32768 (0x8000) in both words indicates that

the mouse was released outside of slopRect . In this case, the region

should not be moved.

Notes: This function works intuitively, as you come to expect dragging operations

to work:

Drags normally while in limitRect "Pinned" to limitRect

• When the mouse is inside limitRect , the region's outline follows it

normally. If the mouse is released there, the region should be moved to the

new position.

• When the mouse is outside of limitRect but inside of slopRect , the mouse

point is pinned to the border of limitRect . If the mouse is released there,

the region should be moved to its pinned location.

• When the mouse goes outside of slopRect, the outline disappears until the

mouse moves back inside. If the mouse is released outside of slopRect , you

should not move the region.

This call does not redraw the region. Upon return, you should move (i.e.,

redraw) the region or abort the move, as described above.

This call modifies the region, so you may wish to make a copy (via

NewRgn and CopyRgn) and pass its handle as theRgn .

Use DragWindow to let a user reposition a window.

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