TRACK.C
/******************************************************************************\
* This is a part of the Microsoft Source Code Samples.
* Copyright 1992 - 1998 Microsoft Corporation.
* All rights reserved.
* This source code is only intended as a supplement to
* Microsoft Development Tools and/or WinHelp documentation.
* See these sources for detailed information regarding the
* Microsoft samples programs.
\******************************************************************************/
/**************************************************************************\
* track.c -- support for direct manipulation of parallelogram object.
\**************************************************************************/
#include <windows.h>
#include <math.h>
#include "track.h"
#define EPSILON (float) 0.0001
#define RECTSIZE 60
/**************************************************************************\
*
* function: doTrackObject()
*
* input parameters:
* pto - pointer to a track object.
* msg - message selecting what action to take. Values may include WM_*'s
* (see case statements below for more information.)
* hwnd - Window handle for the window the track object exists within.
* lParam - Usually fourth param to window proc. varies based on msg.
*
* global variables: none.
*
* coordinate spaces: There are three coordinate spaces of interest here,
* and this routine is frequently switching between them...
*
* WORLD DEVICE SCREEN
*
* object coordinates input mouse pos used w/ SetCursorPos()
* (pto->rect) (lParam for WM_*)
*
* -----> LPtoDP() ----> ----> ClientToScreen() -->
* <----- DPtoLP() <---- <---- ScreenToClient() <--
*
* in addition, the HDC has an offset origin. Device coordinates for the
* mouse (lParam) never take this into account, but it is necessary to
* translate them in order to get direct manipulation right.
*
\**************************************************************************/
PTrackObject doTrackObject(PTrackObject pto, int msg, HWND hwnd, LONG lParam)
{
if ((pto == NULL) && (msg != TROB_NEW)) return NULL;
switch (msg) {
/**********************************************************************\
* TROB_NEW
*
* Allocate new PTrackObject structure. Fill in default values
* for the fields of the structure. Set up the HDC correctly.
* return - pointer to the new object.
\**********************************************************************/
case TROB_NEW: {
PTrackObject pto;
/* with LPTR returned value is a pointer. */
pto = (PTrackObject) LocalAlloc (LPTR, sizeof (TrackObject));
/* initialize the HDC and other fields. */
pto->hdc = GetDC (hwnd);
SetGraphicsMode (pto->hdc, GM_ADVANCED);
SetROP2(pto->hdc, R2_NOT);
SelectObject (pto->hdc, GetStockObject (NULL_BRUSH));
pto->Mode = TMNONE;
pto->allowedModes = TMMOVE | TMSIZEXY;
GetWorldTransform (pto->hdc, &(pto->xfmChange));
/* initialize the size. */
pto->rect.top = pto->rect.left = 0;
pto->rect.bottom = pto->rect.right = RECTSIZE;
return (pto);
}
/**********************************************************************\
* TROB_DELETE
*
* Complement of TROB_NEW. Free up the memory allocated for the object.
\**********************************************************************/
case TROB_DELETE:
doTrackObject (pto, TROB_PAINT, hwnd, lParam);
ReleaseDC (hwnd, pto->hdc);
LocalFree (LocalHandle ((LPSTR)pto));
return NULL;
/**********************************************************************\
* TROB_PAINT
*
* Paint the object into its hdc. Called half the time to erase
* the object, and half the time to redraw it.
\**********************************************************************/
case TROB_PAINT: {
MoveToEx (pto->hdc, pto->rect.right, pto->rect.top, NULL);
LineTo (pto->hdc, pto->rect.left, pto->rect.top);
LineTo (pto->hdc, pto->rect.left, pto->rect.bottom);
if (pto->allowedModes & TMSIZEXY) {
LineTo (pto->hdc, pto->rect.right, pto->rect.bottom);
LineTo (pto->hdc, pto->rect.right, pto->rect.top);
}
if (pto->allowedModes & TMROTATE) {
MoveToEx (pto->hdc, pto->rect.left, pto->rect.bottom/ 4, NULL);
AngleArc (pto->hdc, pto->rect.left, pto->rect.top,
(DWORD) pto->rect.bottom/ 4, (float) 270.0, (float) 90.0);
}
} return NULL;
/**********************************************************************\
* TROB_HITTEST
*
* Check the point sent in in the lParam to see if it lays within
* the bounds of the objects defining rectangle.
* return - pointer to the object iff the point is in rectangle,
* otherwise return NULL.
\**********************************************************************/
case TROB_HITTEST:{
POINT mouWorld;
mouWorld.x = LOWORD(lParam);
mouWorld.y = HIWORD(lParam);
DPtoLP (pto->hdc, &mouWorld, 1);
if (PtInRect (&pto->rect, mouWorld)) return pto;
else return NULL;
}
/**********************************************************************\
* WM_LBUTTONDOWN & WM_RBUTTONDOWN
*
* Capture the mouse, set the tracking mode depending on the mouse
* location in world coordinates, reset the mouse position.
*
\**********************************************************************/
case WM_LBUTTONDOWN:
case WM_RBUTTONDOWN: {
POINT newmouScreen;
POINT mouWorld;
mouWorld.x = LOWORD(lParam);
mouWorld.y = HIWORD(lParam);
DPtoLP (pto->hdc, &mouWorld, 1);
/* upper left hand corner. right button is no-op. */
if ((mouWorld.x <= (pto->rect.right / 2)) &&
(mouWorld.y <= (pto->rect.bottom / 2))) {
if (msg == WM_RBUTTONDOWN) return NULL;
pto->Mode = TMMOVE;
newmouScreen.x = pto->rect.left;
newmouScreen.y = pto->rect.top;
/* lower left hand corner */
} else if ((mouWorld.x <= (pto->rect.right / 2)) &&
(mouWorld.y > (pto->rect.bottom / 2))) {
pto->Mode = (msg == WM_RBUTTONDOWN) ? TMSHEARY : TMSIZEY;
newmouScreen.x = pto->rect.left;
newmouScreen.y = pto->rect.bottom;
/* upper right hand corner */
} else if ((mouWorld.x > (pto->rect.right / 2)) &&
(mouWorld.y <= (pto->rect.bottom / 2))) {
pto->Mode = (msg == WM_RBUTTONDOWN) ? TMSHEARX : TMSIZEX;
newmouScreen.x = pto->rect.right;
newmouScreen.y = pto->rect.top;
/* lower right hand corner */
} else if ((mouWorld.x > (pto->rect.right / 2)) &&
(mouWorld.y > (pto->rect.bottom / 2))) {
pto->Mode = (msg == WM_RBUTTONDOWN) ? TMROTATE : TMSIZEXY;
newmouScreen.x = pto->rect.right;
newmouScreen.y = pto->rect.bottom;
}
if (! (pto->Mode & pto->allowedModes)) {
pto->Mode = TMNONE;
return NULL;
}
SetCapture(hwnd);
LPtoDP (pto->hdc, &newmouScreen, 1);
ClientToScreen (hwnd, &newmouScreen);
SetCursorPos (newmouScreen.x,newmouScreen.y);
GetWorldTransform (pto->hdc, &pto->xfmDown);
} return NULL;
/**********************************************************************\
* WM_MOUSEMOVE
*
* this is where almost all of the interesting calculation is done.
* First clip the mouse location to be in rectClip, then
* call MouseMove() to handle the different tracking modes.
\**********************************************************************/
case WM_MOUSEMOVE: {
if ((short) LOWORD(lParam) < (short)pto->rectClip.left)
lParam = MAKELONG ((WORD)pto->rectClip.left, HIWORD(lParam));
if (LOWORD(lParam) > (WORD)pto->rectClip.right)
lParam = MAKELONG ((WORD)pto->rectClip.right, HIWORD(lParam));
if ((short) HIWORD(lParam) < (short)pto->rectClip.top)
lParam = MAKELONG (LOWORD(lParam), (WORD)pto->rectClip.top);
if (HIWORD(lParam) > (WORD)pto->rectClip.bottom)
lParam = MAKELONG (LOWORD(lParam),(WORD)pto->rectClip.bottom);
MouseMove (pto, msg, hwnd, lParam);
} return NULL;
/**********************************************************************\
* WM_RBUTTONUP & WM_LBUTTONUP
*
* simply release the mouse capture, and set the mode to TMNONE.
\**********************************************************************/
case WM_RBUTTONUP:
case WM_LBUTTONUP: {
if (pto->Mode) {
ReleaseCapture();
pto->Mode = TMNONE;
}
} return NULL;
} /* end switch(msg) */
}
/**************************************************************************\
* function: MouseMove()
*
* input parameters:
* pto - pointer to a track object.
* msg - not used.
* hwnd - Window handle for the window the track object exists within.
* lParam - Usually fourth param to window proc. varies based on msg.
*
* The tracking behavior which the user observers when moving the mouse
* is based on the current tracking mode of the object. This is usually
* determined on the mouse down event (c.f. TM*). First erase the old
* object, then figure out the change to the transform matrix, finally
* change the world transform matrix and redraw the object.
*
* Tranform:
* ( eM11 eM12 0 )
* ( eM21 eM22 0 )
* ( eDx eDy 1 )
*
* xDevice = (xWorld * eM11) + (yWorld * eM21) + eDx
* yDevice = (xWorld * eM12) + (yWorld * eM22) + eDy
*
* In this routine the Device (mouse location) and World (rectangle corner)
* points are known. Therefore, the two equations above are solved for
* the desired matrix entry value (e.g. eM11, 1M12, ... eDy). The tracking
* mode determines which one of these entries may be changed. E.g. scaling
* in X modifies eM11 while shearing in X modifies eM12. So rather than
* using the world transform to map from world to device points, we are
* back-computing the proper contents of the world transform.
*
\**************************************************************************/
VOID MouseMove(PTrackObject pto, int msg, HWND hwnd, LONG lParam)
{
POINT mouWorld, mouDevice, orgDevice;
UNREFERENCED_PARAMETER(msg);
doTrackObject(pto, TROB_PAINT, hwnd, lParam);
mouDevice.x = mouWorld.x = LOWORD(lParam);
mouDevice.y = mouWorld.y = HIWORD(lParam);
SetWorldTransform(pto->hdc, &pto->xfmDown);
DPtoLP (pto->hdc, &mouWorld, 1);
/* offset the mouse device point for the viewport's origin. */
GetViewportOrgEx (pto->hdc, &orgDevice);
mouDevice.x -= orgDevice.x;
mouDevice.y -= orgDevice.y;
GetWorldTransform(pto->hdc, &pto->xfmChange);
switch (pto->Mode) {
/*******************************************************\
* ( 1 xShear 0 )
* ( 0 1 0 )
* ( 0 0 1 )
*
* xWorld = rect.left == 0;
\*******************************************************/
case TMSHEARX: {
pto->xfmChange.eM12 = (float) mouDevice.y;
pto->xfmChange.eM12 -=pto->xfmChange.eDy;
pto->xfmChange.eM12 /=(float) pto->rect.right ;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( 1 0 0 )
* ( yShear 1 0 )
* ( 0 0 1 )
*
* yWorld = rect.top == 0;
\*******************************************************/
case TMSHEARY: {
pto->xfmChange.eM21 = (float) mouDevice.x;
pto->xfmChange.eM21 -=pto->xfmChange.eDx;
pto->xfmChange.eM21 /=(float) pto->rect.bottom ;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( cos(a) -sin(a) 0 )
* ( sin(a) cos(a) 0 )
* ( 0 0 1 )
*
* a == rotation angle. Since mouse in in lower right,
* we need to shift this back 45 degrees (assuming that
* straight down is 0 degrees). Thus we actually compute
* cos(a) = cos(b - 45) = cos(b)sin(45) + cos(45)sin(45)
* where b is angle from the origin to the mouse (x,y)
* cos(45) = sin(45) ~= 0.707107
* cos(b) = y/r sin(b) = x/r
*
\*******************************************************/
case TMROTATE: {
float r;
/* translate back to the origin. */
pto->xfmChange.eDx = pto->xfmChange.eDy = (float)0.0;
SetWorldTransform (pto->hdc, &pto->xfmChange);
/* rotate about the origin. */
r = (float) sqrt( (double)(mouWorld.x * mouWorld.x) +
(double)(mouWorld.y * mouWorld.y));
pto->xfmChange.eM11 = (float) mouWorld.y / r;
pto->xfmChange.eM11 += (float) mouWorld.x / r;
pto->xfmChange.eM11 *= (float) 0.707107;
pto->xfmChange.eM22 = pto->xfmChange.eM11;
pto->xfmChange.eM12 = (float) mouWorld.y / r;
pto->xfmChange.eM12 -= (float) mouWorld.x / r;
pto->xfmChange.eM12 *= (float) 0.707107;
pto->xfmChange.eM21 = -pto->xfmChange.eM12;
pto->xfmChange.eDx = pto->xfmChange.eDy = (float)0.0;
ModifyWorldTransform (pto->hdc, &pto->xfmChange, MWT_RIGHTMULTIPLY);
/* translate back to the original offset. */
pto->xfmChange.eM11 =
pto->xfmChange.eM22 = (float) 1.0;
pto->xfmChange.eM12 =
pto->xfmChange.eM21 = (float) 0.0;
pto->xfmChange.eDx = pto->xfmDown.eDx;
pto->xfmChange.eDy = pto->xfmDown.eDy;
ModifyWorldTransform (pto->hdc, &pto->xfmChange, MWT_RIGHTMULTIPLY);
GetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( Size X 0 0 )
* ( 0 Size Y 0 )
* ( 0 0 1 )
*
\*******************************************************/
case TMSIZEXY: {
pto->xfmChange.eM11 = (float) mouDevice.x;
pto->xfmChange.eM11 -=pto->xfmChange.eDx;
pto->xfmChange.eM11 -=((float) pto->rect.bottom*pto->xfmChange.eM21);
pto->xfmChange.eM11 /=(float) pto->rect.right ;
if (fabs(pto->xfmChange.eM11) < EPSILON) // HACK. system bug ?
pto->xfmChange.eM11 = EPSILON;
pto->xfmChange.eM22 = (float) mouDevice.y;
pto->xfmChange.eM22 -=pto->xfmChange.eDy;
pto->xfmChange.eM22 -=((float) pto->rect.right*pto->xfmChange.eM12);
pto->xfmChange.eM22 /=(float) pto->rect.bottom ;
if (fabs(pto->xfmChange.eM22) < EPSILON) // HACK. system bug ?
pto->xfmChange.eM22 = EPSILON;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( Size X 0 0 )
* ( 0 1 0 )
* ( 0 0 1 )
*
* yWorld = rect.top == 0;
\*******************************************************/
case TMSIZEX: {
pto->xfmChange.eM11 = (float) mouDevice.x;
pto->xfmChange.eM11 -=pto->xfmChange.eDx;
pto->xfmChange.eM11 /=(float) pto->rect.right ;
if (fabs(pto->xfmChange.eM11) < EPSILON) // HACK. system bug ?
pto->xfmChange.eM11 = EPSILON;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( 1 0 0 )
* ( 0 Size Y 0 )
* ( 0 0 1 )
*
* xWorld = rect.left == 0;
\*******************************************************/
case TMSIZEY: {
pto->xfmChange.eM22 = (float) mouDevice.y;
pto->xfmChange.eM22 -=pto->xfmChange.eDy;
pto->xfmChange.eM22 /=(float) pto->rect.bottom ;
if (fabs(pto->xfmChange.eM22) < EPSILON) // HACK. system bug ?
pto->xfmChange.eM22 = EPSILON;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
/*******************************************************\
* ( 1 0 0 )
* ( 0 1 0 )
* ( Move x Move y 1 )
*
* xWorld = rect.left == 0;
* yWorld = rect.top == 0;
\*******************************************************/
case TMMOVE: {
pto->xfmChange.eDx = (float) mouDevice.x ;
pto->xfmChange.eDy = (float) mouDevice.y ;
SetWorldTransform (pto->hdc, &pto->xfmChange);
} break;
} /* end switch */
doTrackObject(pto, TROB_PAINT, hwnd, lParam);
return;
}