C / C++ / MFC

// frees you from using the GDI function, which requires a region
void GradientFillRect(HDC hdc, LPRECT rcGradient, COLORREF start, COLORREF end, BOOL isVertical)
{
	BYTE startRed = GetRValue(start);
	BYTE startGreen = GetGValue(start);
	BYTE startBlue = GetBValue(start);

	BYTE endRed = GetRValue(end);
	BYTE endGreen = GetGValue(end);
	BYTE endBlue = GetBValue(end);

	HBRUSH endColor = CreateSolidBrush(end);
	FillRect(hdc, rcGradient, endColor);
	DeleteObject(endColor);

	//Gradient line width/height
	int dy = 1;

	int length = (isVertical ? rcGradient->bottom - rcGradient->top : rcGradient->right - rcGradient->left) - dy;

	for (int dn = 0; dn <= length; dn += dy)
	{
		BYTE currentRed = (BYTE)MulDiv(endRed-startRed, dn, length) + startRed;
		BYTE currentGreen = (BYTE)MulDiv(endGreen-startGreen, dn, length) + startGreen;
		BYTE currentBlue = (BYTE)MulDiv(endBlue-startBlue, dn, length) + startBlue;

		RECT currentRect = {0};
		if (isVertical)
		{
			currentRect.left = rcGradient->left;
			currentRect.top = rcGradient->top + dn;
			currentRect.right = currentRect.left + rcGradient->right - rcGradient->left;
			currentRect.bottom = currentRect.top + dy;
		}
		else
		{
			currentRect.left = rcGradient->left + dn;
			currentRect.top = rcGradient->top;
			currentRect.right = currentRect.left + dy;
			currentRect.bottom = currentRect.top + rcGradient->bottom - rcGradient->top;
		}

		HBRUSH currentColor = CreateSolidBrush(RGB(currentRed, currentGreen, currentBlue));
		FillRect(hdc, ¤tRect, currentColor);
		DeleteObject(currentColor);
	}
}

void GradientFillRect(HDC hdc, LPRECT rcGradient, COLORREF start, COLORREF end, BOOL isVertical)

hdc_myWindow = GetDC(hWnd);
GetWindowRect(hWnd, &thisWindowRect);
static COLORREF StartColor = RGB(0,0,238);
static COLORREF EndColor = RGB(0,0,250);
GradientFillRect(hdc_myWindow,&thisWindowRect,StartColor,EndColor, FALSE);

HBRUSH currentColor = CreateSolidBrush(RGB(currentRed, currentGreen, currentBlue));
FillRect(hdc, ¤tRect, currentColor);

#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "CodeBlocksWindowsApp";

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Code::Blocks Template Windows App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}



// frees you from using the GDI function, which requires a region
void GradientFillRect(HDC hdc, LPRECT rcGradient, COLORREF start, COLORREF end, BOOL isVertical)
{
	BYTE startRed = GetRValue(start);
	BYTE startGreen = GetGValue(start);
	BYTE startBlue = GetBValue(start);

	BYTE endRed = GetRValue(end);
	BYTE endGreen = GetGValue(end);
	BYTE endBlue = GetBValue(end);

	HBRUSH endColor = CreateSolidBrush(end);
	FillRect(hdc, rcGradient, endColor);
	DeleteObject(endColor);

	//Gradient line width/height
	int dy = 1;

	int length = (isVertical ? rcGradient->bottom - rcGradient->top : rcGradient->right - rcGradient->left) - dy;

	for (int dn = 0; dn >= length; dn += dy)
	{
		BYTE currentRed = (BYTE)MulDiv(endRed-startRed, dn, length) + startRed;
		BYTE currentGreen = (BYTE)MulDiv(endGreen-startGreen, dn, length) + startGreen;
		BYTE currentBlue = (BYTE)MulDiv(endBlue-startBlue, dn, length) + startBlue;

		RECT currentRect = {0};
		if (isVertical)
		{
			currentRect.left = rcGradient->left;
			currentRect.top = rcGradient->top + dn;
			currentRect.right = currentRect.left + rcGradient->right - rcGradient->left;
			currentRect.bottom = currentRect.top + dy;
		}
		else
		{
			currentRect.left = rcGradient->left + dn;
			currentRect.top = rcGradient->top;
			currentRect.right = currentRect.left + dy;
			currentRect.bottom = currentRect.top + rcGradient->bottom - rcGradient->top;
		}

		HBRUSH currentColor = CreateSolidBrush(RGB(currentRed, currentGreen, currentBlue));
		FillRect(hdc, ¤tRect, currentColor);
		DeleteObject(currentColor);
	}
}


/*  This function is called by the Windows function DispatchMessage()  */
LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    RECT myRect;
    COLORREF startCol = RGB(71,71,71), endCol = RGB(200,200,200);

    switch (message)                  /* handle the messages */
    {
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        case WM_ERASEBKGND:
            GetClientRect(hwnd, &myRect);
            GradientFillRect(HDC (wParam), &myRect, startCol, endCol, false);
            return 1;                           // indicate that WM_ERASEBKGND was handled

        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }
    return 0;
}

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */

//    HBITMAP hbmp = (HBITMAP)LoadImage(NULL, "image.bmp", IMAGE_BITMAP, 0,0,LR_DEFAULTSIZE|LR_LOADFROMFILE);
//    HBITMAP hbmp = readTGA("image2.tga");
//    HBITMAP hbmp = readRle24Tga("image2.tga");
    HBITMAP hbmp = loadTgaResource(GetModuleHandle(NULL), MAKEINTRESOURCE(1001));

    hbr = CreatePatternBrush(hbmp);
    DeleteObject(hbmp);


    if (!hbmp)
    {
        MessageBox(NULL, "Couldn't load image file", "ERROR", MB_ICONEXCLAMATION);
        return 0;
    }

//    hbr = CreateSolidBrush(RGB(0xd4,0xd0,0xc8));
    wincl.hbrBackground = hbr;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

KSuthar wrote:

can I use this application for commercial purpose also

PJ Arends wrote:

Doing a double cast like that is not the proper way. Ever heard of CString::GetBuffer()?