The problem I am having is that when I draw my line, the screen flickers every time it redraws. I just can't quite figure out how to not make it flicker. I understand the flicker is coming from me redrawing the client area hundreds of times a second as I move my mouse with my left button down but how would I be able to get around this?
LRESULT CALLBACK WndProc (HWND hwnd, UINT message,
WPARAM wParam, LPARAM lParam)
{
static HDC hdc;
PAINTSTRUCT ps;
RECT rect;
RECT size;
static POINT point1;
static POINT point2;
static HBRUSH origBrush;
static bool drawingLine = false;
switch (message)
{
case WM_CREATE:
origBrush = CreateSolidBrush(RGB(0, 0 , 0) );
break;
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps);
GetClientRect (hwnd, &rect);
GetWindowRect(hwnd, &size);
Rectangle(hdc, 10, 10, 80, 80 );
if(drawingLine == true)
{
MoveToEx(hdc, point1.x, point1.y, NULL);
LineTo(hdc, point2.x, point2.y);
}
EndPaint (hwnd, &ps);
return 0;
//Has all the commands that exist in your program.
case WM_COMMAND:
switch(LOWORD(wParam))
{
case ID_COLOR_RED:
break;
case ID_COLOR_BLUE:
break;
case ID_COLOR_BLACK:
break;
case ID_THICKNESS_1:
break;
case ID_THICKNESS_2:
break;
case ID_THICKNESS_3:
break;
}
break;
case WM_LBUTTONDOWN:
drawingLine = true;
SelectObject(hdc, GetStockObject(BLACK_BRUSH));
point1.x = LOWORD(lParam);
point1.y = HIWORD(lParam);
MoveToEx(hdc, point1.x, point1.y, NULL);
break;
case WM_MOUSEMOVE:
point2.x = LOWORD(lParam);
point2.y = HIWORD(lParam);
InvalidateRect(hwnd, NULL, 1);
break;
case WM_LBUTTONUP:
point2.x = LOWORD(lParam);
point2.y = HIWORD(lParam);
drawingLine = false;
break;
//Causes the program to exit.
case WM_DESTROY:
PostQuitMessage(0);
break;
}
The main thing to do is respond to WM_ERASEBKGND and return true to prevent the default re-drawing of the background.
Then you'll need to erase the old line you before drawing the new one. Just for example, you might save bits from under the line, draw it, then restore those (and only those) pixels before drawing the line, so when you need to erase it, you can just restore those pixels to erase it.
The obvious alternative (that's usually simpler though theoretically at least a little slower) is to use double buffering. Do roughly the drawing you are now, but to an off-screen bitmap. Then, when it's all complete just BitBlt from there to the screen.
Related
I'm trying to move static TCHAR greeting[] = _T("123"); by using arrows, but it doesn't move at all. MessageBox is used as a confirmation of getting keyboard input.
void move(HWND hWnd, WPARAM wParam, LPARAM lParam, unsigned int *x, unsigned int * y) {
RECT rt;
if (wParam == VK_LEFT) {
GetClientRect(hWnd, &rt);
x = x - 5;
InvalidateRect(hWnd, &rt, FALSE);
MessageBox(hWnd, LPCSTR("123"), LPCSTR("123"), MB_OK);
}
if (wParam == VK_DOWN) {
GetClientRect(hWnd, &rt);
y = y - 5;
InvalidateRect(hWnd, &rt, FALSE);
}
if (wParam == VK_UP) {
GetClientRect(hWnd, &rt);
y = y + 5;
InvalidateRect(hWnd, &rt, FALSE);
}
if (wParam == VK_RIGHT) {
GetClientRect(hWnd, &rt);
x = x + 5;
InvalidateRect(hWnd, &rt, FALSE);
}
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
PAINTSTRUCT ps;
HDC hdc;
static TCHAR greeting[] = _T("123");
unsigned int x = 50;
unsigned int y = 50;
switch (message)
{
case WM_PAINT: {
hdc = BeginPaint(hWnd, &ps);
TextOut(hdc,
x, y,
greeting, 3);
EndPaint(hWnd, &ps);
break;
}
case WM_KEYDOWN:
move(hWnd, wParam, lParam, &x, &y);
break;
case WM_DESTROY: {
PostQuitMessage(0);
break;
default: {
return DefWindowProc(hWnd, message, wParam, lParam);
break;
}
}
return 0;
}
}
Can somebody explain, what is wrong here? I'm still trying to learn about <Windows.h> so pls don't try to make the code much more complicated.
The x and y variables you are using to draw the text with are local to WndProc and are always reset to the initial values whenever a new message is received. You need to move their declarations outside of WndProc() (or at least make them static) so that their values can persist between messages. You can then update their values in your WM_KEYDOWN handler, and use their current values to draw the text in your WM_PAINT handler.
Also, your move() function is updating the pointers that are pointing at the x and y variables, it is not updating the values of the x and y variables themselves.
Try this instead:
void move(HWND hWnd, WPARAM wParam, LPARAM lParam, unsigned int *x, unsigned int * y) {
switch (wParam) {
case VK_LEFT:
*x -= 5;
InvalidateRect(hWnd, NULL, FALSE);
break;
case VK_DOWN:
*y -= 5;
InvalidateRect(hWnd, NULL, FALSE);
break;
case VK_UP:
*y += 5;
InvalidateRect(hWnd, NULL, FALSE);
break;
case VK_RIGHT:
*x += 5;
InvalidateRect(hWnd, NULL, FALSE);
break;
}
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
static TCHAR greeting[] = _T("123");
static unsigned int x = 50;
static unsigned int y = 50;
switch (message) {
case WM_PAINT: {
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
TextOut(hdc,
x, y,
greeting, 3);
EndPaint(hWnd, &ps);
break;
}
case WM_KEYDOWN:
move(hWnd, wParam, lParam, &x, &y);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
While #Remy Lebeau's answer is right, I don't think I'd write the move function quite the way he has. I'd pass x and y by reference instead of using pointers, and I'd consolidate more of the code together. Oh, and since it doesn't use lParam, we might as well not pass it at all:
void move(HWND hWnd, WPARAM wParam, unsigned int &x, unsigned int & y) {
switch (wParam) {
case VK_LEFT:
x -= 5;
break;
case VK_DOWN:
y -= 5;
break;
case VK_UP:
y += 5;
break;
case VK_RIGHT:
x += 5;
break;
default: return;
}
InvalidateRect(hWnd, NULL, FALSE);
}
Also note, however that this has a little bit of a problem. Passing FALSE as the last parameter to InvalidateRect means it doesn't erase the background. If you move your string around much, you're probably going to end up with artifacts of the movement--fragments of the string showing up in both the previous and the current location.
One easy way to fix that is change the final parameter to TRUE. To make that a bit more efficient, you can calculate the rectangle covering the old and new locations of the string, and invalidate only that much. Alternatively, invalidate the old rectangle with TRUE and the new rectangle with FALSE, and Windows will figure things out from there.
Another possibility (slightly more work, but under the right circumstances it can pay off) is to create an off-screen bitmap containing both your message and a border in the background color that's large enough to cover up the message in its previous location. Then when you move it around, you just blit that bitmap to the screen.
That obviously only works if your background is a solid, uniform color though.
I've a popup window that displays a picture. Each time it displays a picture, the content is changed by another code to make it look like a motion picture.
Without using a while loop, it just displays the picture and the window doesn't hang, it responds perfectly well.
But I'm unable to achieve what I want without a while loop. when I use the while loop to create the motion picture. It works, but after a while the window stops responding.
Here's an example of the window procedure:
LRESULT CALLBACK WindowProcedure(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp){
HDC hdc;
PAINTSTRUCT ps;
switch(msg){
case WM_PAINT:{
hdc = BeginPaint(hWnd, &ps);
Gdiplus::Graphics graph(hdc);
while(true){
Sleep(100);
Image img(L"Test.png");
graph.DrawImage(&img, 0, 0, 1000, 700);
}
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProcW(hWnd,msg,wp,lp);
}
}
As #RetiredNinja said in comments, this code really needs a timer, not a while loop. If you block the window procedure, the window will stop responding to messages. You must return flow to the thread's message loop after each message is processed.
At startup, load your initial image, start the timer, and invalidate the window. Done.
Whenever the timer fires, update the image as needed and invalidate the window to trigger a repaint. Done.
Every time the window procedure receives a WM_PAINT message, draw the current image as-is onto the window. Done.
That is all you need to do. No threads are needed. And the app remains responsive at all times, because no single message is blocked for more than a few milliseconds.
Try something more like this instead:
Image *img = nullptr;
LRESULT CALLBACK WindowProcedure(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp){
switch(msg){
case WM_CREATE:
img = Image::fromFile(L"Test.png", FALSE);
SetTimer(hWnd, 1, 100, NULL);
break;
case WM_DESTROY:
KillTimer(hWnd, 1);
delete img;
PostQuitMessage(0);
break;
case WM_TIMER:{
// update img as needed...
InvalidateRect(hWnd, NULL, TRUE);
break;
}
case WM_PAINT:{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
Gdiplus::Graphics graph(hdc);
graph.DrawImage(img, 0, 0, 1000, 700);
EndPaint(hWnd, &ps);
break;
}
default:
return DefWindowProcW(hWnd, msg, wp, lp);
}
return 0;
}
I want to draw the line by clicking the mouse on the first coordinate where the line should start and second coordinate where the line should end.
When I run my project nothing happens.
I cannot find out what my code is missing.
LONG WINAPI WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
BOOL fDraw = FALSE;
POINT ptPrevious = { 0 };
HPEN Pen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255));
switch (Message) {
case WM_LBUTTONDOWN: {
fDraw = TRUE;
ptPrevious.x = LOWORD(lParam);
ptPrevious.y = HIWORD(lParam);
break;
}
case WM_LBUTTONUP: {
if (fDraw)
{
hdc = GetDC(hWnd);
MoveToEx(hdc, ptPrevious.x, ptPrevious.y, NULL);
LineTo(hdc, LOWORD(lParam), HIWORD(lParam));
ReleaseDC(hWnd, hdc);
}
fDraw = FALSE;
break;
}
case WM_MOUSEMOVE: {
if (fDraw)
{
hdc = GetDC(hWnd);
MoveToEx(hdc, ptPrevious.x, ptPrevious.y, NULL);
LineTo(hdc, ptPrevious.x = LOWORD(lParam),
ptPrevious.y = HIWORD(lParam));
ReleaseDC(hWnd, hdc);
}
break;
}
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, Message, wParam, lParam);
}
return 0;
}
Fundamentally, the problem is because none of your data is persistent. Since they are all local variables, their content disappears when WndProc returns. fDraw is set to FALSE on every message, and will never be true for the WM_LBUTTONDOWN or WM_MOUSEMOVE messages. Therefore nothing happens.
You'll want to create some sort of a class to hold fDraw, ptPrevious, and a structure to hold the coordinates of the line(s) to draw. Use InvalidateRect in the WM_MOUSEMOVE and WM_LBUTTONUP messages. Then only draw them in response to a WM_PAINT message (using the DC provided in the paint message).
Using the CWnd MFC class can greatly simplify those tasks.
Because declared variables are local variables, variables can be declared with Static.
static BOOL fDraw = FALSE;
static POINT ptPrevious = { 0 };
In addition, you forget to use the SelectObject function to select pen into DC.
You can also use WM_PAINT redrawing to improve your code:
Example:
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
static BOOL fDraw = FALSE;
static BOOL fDraw_begin = FALSE;
static POINT ptPrevious;
static RECT rcClient;
static POINT pt;
static HPEN Pen;
switch (message)
{
case WM_CREATE:
{
Pen = CreatePen(PS_SOLID, 3, RGB(255, 0, 0));
break;
}
case WM_LBUTTONDOWN:
{
ptPrevious.x = (LONG)LOWORD(lParam);
ptPrevious.y = (LONG)HIWORD(lParam);
return 0;
}
case WM_LBUTTONUP:
{
if (fDraw = TRUE)
{
fDraw = FALSE;
fDraw_begin = TRUE;
InvalidateRect(hwnd, &rcClient, TRUE);
UpdateWindow(hwnd);
}
return 0;
}
case WM_MOUSEMOVE:
{
if (wParam && MK_LBUTTON)
{
GetClientRect(hwnd, &rcClient);
hdc = GetDC(hwnd);
SetROP2(hdc, R2_NOTXORPEN);
if (!IsRectEmpty(&rcClient)) // Detecting whether the rectangular area is empty
{
MoveToEx(hdc, ptPrevious.x, ptPrevious.y, NULL);
LineTo(hdc, (LONG)LOWORD(lParam),
(LONG)HIWORD(lParam));
}
MoveToEx(hdc, ptPrevious.x, ptPrevious.y, NULL);
LineTo(hdc, (LONG)LOWORD(lParam),
(LONG)HIWORD(lParam));
pt.x = (LONG)LOWORD(lParam);
pt.y = (LONG)HIWORD(lParam);
fDraw = TRUE;
ReleaseDC(hwnd, hdc);
}
return 0;
}
case WM_PAINT:
{
hdc = BeginPaint(hwnd, &ps);
SelectObject(hdc, Pen);
if (fDraw_begin)
{
fDraw_begin = FALSE;
MoveToEx(hdc, ptPrevious.x, ptPrevious.y, NULL);
LineTo(hdc, pt.x,
pt.y);
}
EndPaint(hwnd, &ps);
ReleaseDC(hwnd, hdc);
return 0;
}
case WM_DESTROY:
{
DeleteObject(Pen);
PostQuitMessage(0);
return 0;
}
}
return DefWindowProc(hwnd, message, wParam, lParam);
}
Do not get the DC three times, get it once and release it on mouse up.
Also, your drawing will be eventually validated, so you need to log the mouse move and repeat this stuff in WM_PAINT handler.
I'm new and I'm trying to write a simple program drawing lines with the mouse.
I have a problem with drawing these lines, because it leaves traces behind.
Here is an image of my problem:
And here is a sample of my code:
LRESULT APIENTRY WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY:PostQuitMessage(0);break;
case WM_LBUTTONDOWN:
hdc = GetDC(hwnd);
last_x = LOWORD(lParam);
last_y = HIWORD(lParam);
isDown = true;
break;
case WM_MOUSEMOVE:
if (isDown)
{
Pen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255));
Box = (HPEN)SelectObject(hdc, Pen);
int x = LOWORD(lParam);
int y = HIWORD(lParam);
MoveToEx(hdc, last_x, last_y, NULL);
LineTo(hdc, x, y);
}
break;
case WM_LBUTTONUP:
isDown = false;
ReleaseDC;
break;
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
EDIT:
Now it's working well, but if You could explain me one another thing, how can i make that my old lines stayed on the Client area when i drawing new lines? Cause now i can draw only one line. Should i use Bitmap to save screen or something?
EDIT:EDIT:
Ok i used Vector to save coordinates of every line. Thank You guys for help!
You are getting residual traces because you are not erasing your old drawings before drawing a new line, or at least updating last_x and last_y on each move so that a new line connects to the end of the previous line, like in Microsoft's example.
But, you really should not draw on the window directly in the mouse message handlers at all. As soon as the window needs a repaint for any reason, all of your drawing will be lost. The correct way to handle this is to perform all of your drawing in a WM_PAINT message handler instead. Use the mouse messages to keep track of line information as needed, and then do all of the actual drawing in WM_PAINT only.
For example:
LRESULT APIENTRY WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CREATE:
Pen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255));
break;
case WM_DESTROY:
DeleteObject(Pen);
PostQuitMessage(0);
break;
case WM_LBUTTONDOWN:
x = last_x = LOWORD(lParam);
y = last_y = HIWORD(lParam);
isDown = true;
InvalidateRect(hwnd, NULL, TRUE);
break;
case WM_MOUSEMOVE:
if (isDown)
{
x = LOWORD(lParam);
y = HIWORD(lParam);
InvalidateRect(hwnd, NULL, TRUE);
}
break;
case WM_LBUTTONUP:
isDown = false;
InvalidateRect(hwnd, NULL, TRUE);
break;
/* if your WNDCLASS sets hbrBackground=NULL, uncomment this handler...
case WM_ERASEBKGND:
{
HDC hdc = (HDC) wParam;
draw a background on the hdc as needed...
return 1;
}
*/
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hwnd, &ps);
if (last_x != x) || (last_y != y)
{
HPEN OldPen = (HPEN) SelectObject(hdc, Pen);
MoveToEx(hdc, last_x, last_y, NULL);
LineTo(hdc, x, y);
SelectObject(hdc, OldPen);
}
EndPaint(hwnd, &ps);
break;
}
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
That will draw a single line that starts at the point where the mouse was first held down, and then follow the mouse as it moves around.
Or, if you want to draw multiple lines end-to-end that follow the mouse while it is held down, try this:
std::vector<POINT> points;
LRESULT APIENTRY WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CREATE:
Pen = CreatePen(PS_SOLID, 3, RGB(0, 0, 255));
points.clear();
break;
case WM_DESTROY:
DeleteObject(Pen);
PostQuitMessage(0);
break;
case WM_LBUTTONDOWN:
{
points.clear();
POINT pt;
pt.x = LOWORD(lParam);
pt.y = HIWORD(lParam);
points.push_back(pt);
isDown = true;
InvalidateRect(hwnd, NULL, TRUE);
break;
}
case WM_MOUSEMOVE:
if (isDown)
{
POINT pt;
pt.x = LOWORD(lParam);
pt.y = HIWORD(lParam);
points.push_back(pt);
InvalidateRect(hwnd, NULL, TRUE);
}
break;
case WM_LBUTTONUP:
isDown = false;
InvalidateRect(hwnd, NULL, TRUE);
break;
/* if your WNDCLASS sets hbrBackground=NULL, uncomment this handler...
case WM_ERASEBKGND:
{
HDC hdc = (HDC) wParam;
draw a background on the hdc as needed...
return 1;
}
*/
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hwnd, &ps);
if (points.size() > 1)
{
HPEN OldPen = (HPEN) SelectObject(hdc, Pen);
MoveToEx(hdc, points[0].x, points[0].y, NULL);
for (size_t i = 1; i < points.size(); ++i) {
LineTo(hdc, points[i].x, points[i].y);
}
SelectObject(hdc, OldPen);
}
EndPaint(hwnd, &ps);
break;
}
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
I am late to party here and it may be obvious to experienced Win32 programmers, but I wanted to add an important note to Remy Lebeau example:
both the boolean isDown and the 4 ints x,y,last_x and last_y have to be static, or else the entire solution won't work.
I am trying to draw a rectangle as you left click on a point and then drag across , while your dragging across the rectangle gets form to show you a preview of how the rectangle will look . This works fine except when I drag back into a smaller rectangle the old rectangles still remain.
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
// TODO: Add any drawing code here...
if(painting)
{
HPEN greenPen=CreatePen(PS_SOLID, 1, RGB(0,255,0));
SelectObject(hdc,greenPen);
Rectangle(hdc, x1, y1, x2, y2);
}
EndPaint(hWnd, &ps);
break;
case WM_LBUTTONDOWN:
painting=true;
x1=LOWORD(lParam);
y1=HIWORD(lParam);
InvalidateRect(hWnd, NULL ,false);
break;
case WM_MOUSEMOVE:
x2=LOWORD(lParam);
y2=HIWORD(lParam);
InvalidateRect(hWnd, NULL ,false);
break;
case WM_LBUTTONUP:
painting=false;
break;
#user1788175 - just use a RECT struct. When the drawing starts, you set the left & top members to the x,y pos of the mouse. When the mouse is released, set the right,bottom members. Swap left,right if necessary, to ensure that left
Here's some code ripped from a class I wrote to deal with with selection rectangles. You can ignore the normalize code - it just converts the pixel coordinates to ones in the range [0..1], so I can draw the selection on a scaled-down version of the image, yet still select the same region if the image is shown at a different scale. My images were 4944x6992, so I had to display a scaled-down version of them.
LRESULT CALLBACK cSelBoxImg::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
RECT mappedRect, tmpRect, myRect;
HBRUSH myBrush;
BITMAP bm;
PAINTSTRUCT ps;
HDC mDC;
HBITMAP tmpBmp;
switch (uMsg)
{
case WM_LBUTTONDOWN:
if (bMouseSelectionEnabled)
{
bRubberBanding = true;
mouseClickDownPos.x = LOWORD(lParam);
mouseClickDownPos.y = HIWORD(lParam);
curMousePos = mouseClickDownPos;
selectionRect.left = min(curMousePos.x, mouseClickDownPos.x);
selectionRect.right = max(curMousePos.x, mouseClickDownPos.x);
selectionRect.top = min(curMousePos.y, mouseClickDownPos.y);
selectionRect.bottom = max(curMousePos.y, mouseClickDownPos.y);
normalizeSelRect();
InvalidateRect(mHwnd, NULL, isBkgTransparent);
PostMessage(GetParent(hWnd), WM_COMMAND, GetDlgCtrlID(hWnd), (LPARAM)hWnd);
}
return 1;
case WM_LBUTTONUP:
if (bMouseSelectionEnabled)
if (bRubberBanding)
{
bRubberBanding = false;
mouseClickUpPos.x = LOWORD(lParam);
mouseClickUpPos.y = HIWORD(lParam);
selectionRect.left = min(mouseClickUpPos.x, mouseClickDownPos.x);
selectionRect.right = max(mouseClickUpPos.x, mouseClickDownPos.x);
selectionRect.top = min(mouseClickUpPos.y, mouseClickDownPos.y);
selectionRect.bottom = max(mouseClickUpPos.y, mouseClickDownPos.y);
normalizeSelRect();
InvalidateRect(mHwnd, NULL, isBkgTransparent);
PostMessage(GetParent(hWnd), WM_COMMAND, GetDlgCtrlID(hWnd), (LPARAM)hWnd);
}
return 1;
case WM_MOUSEMOVE:
if (bMouseSelectionEnabled)
if (bRubberBanding)
{
curMousePos.x = LOWORD(lParam);
curMousePos.y = HIWORD(lParam);
selectionRect.left = min(curMousePos.x, mouseClickDownPos.x);
selectionRect.right = max(curMousePos.x, mouseClickDownPos.x);
selectionRect.top = min(curMousePos.y, mouseClickDownPos.y);
selectionRect.bottom = max(curMousePos.y, mouseClickDownPos.y);
// UpdateWindow(hWnd);
//RedrawWindow(hWnd, NULL, NULL, RDW_UPDATENOW);
normalizeSelRect();
InvalidateRect(hWnd, NULL, false);
PostMessage(GetParent(hWnd), WM_COMMAND, GetDlgCtrlID(hWnd), (LPARAM)hWnd);
// printf("Message posted\n");
}
return 0;
case WM_PAINT:
mDC = BeginPaint(hWnd, &ps);
GetClientRect(hWnd, &tmpRect);
// GetObject(mBmp, sizeof(bm), &bm);
mappedRect.left = mLeft * tmpRect.right;
mappedRect.right = mRight * tmpRect.right;
mappedRect.top = mTop * tmpRect.bottom;
mappedRect.bottom = mBottom * tmpRect.bottom;
displayImage();
if (mBmp) drawRect(mDC, mappedRect, RGB(0,0,255));
DeleteObject(tmpBmp);
EndPaint(hWnd, &ps);
return 0;
case WM_ERASEBKGND:
if (isBkgTransparent)
{
GetClientRect(hWnd, &myRect);
myBrush = (HBRUSH) GetWindowLong(hWnd, GCL_HBRBACKGROUND);
FillRect((HDC)wParam, &myRect, myBrush);
printf("background cleared\n");
}
return true;
case WM_SETCURSOR:
SetCursor(mCursor);
return true;
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}