text drawn in a window

closed account (zwA4jE8b)
Some of you have seen this code in a previous post.

I am wondering is there a way to draw the text as a separate object? Bad wording I know. What I want is the text (line 165-167) displayed but not scrolled. 

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//Michael Ervin - Windows Sine Wave

#include <Windows.h>
#include <math.h>
#include <string>
#include <sstream>

#define screen_width 800
#define screen_height 600
#define pi 3.14159

struct _points
{
	int _x;
	int _y;
};

struct _ycoords
{
	_points _one;
	_points _two;
} _yc;

COLORREF blue = RGB(0, 0, 255);
HDC hDC;
HWND hWnd;
std::string _amplitude, _frequency, _speed;

double _freq = 50;
int _sTime = 10, _amp = 100;

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
void calcwave();
void drawwave();
std::string convstr(const int& t);

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
	WNDCLASSEXA wc;

	ZeroMemory(&wc, sizeof(WNDCLASSEX));
	ZeroMemory(&_yc, sizeof(_yc));
	_yc._one._x = 600;
	_yc._two._x = 599;
	_yc._two._y = 300;

	wc.cbSize = sizeof(WNDCLASSEX);
	wc.style = CS_HREDRAW | CS_VREDRAW;
	wc.lpfnWndProc = WindowProc;
	wc.hInstance = hInstance;
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hIcon = (HICON)LoadImageA(NULL, "C:\\Visual Studio 2010\\Icons\\Smiley.ico", IMAGE_ICON, 0, 0, LR_LOADFROMFILE);
	wc.lpszClassName = "SineWave";

	RegisterClassExA(&wc);

	hWnd = CreateWindowExA(NULL,
                          "SineWave", "SineWave",
                          WS_SYSMENU,
                          0, 45,
                          screen_width, screen_height,
                          NULL, NULL,
                          hInstance,
                          NULL);

	ShowWindow(hWnd, nCmdShow);
	hDC = GetDC(hWnd);

	HPEN _Pen = CreatePen(PS_SOLID, 1, blue);
	SelectObject(hDC, _Pen);

	MSG msg;

	while(TRUE)
	{
		while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
		{DispatchMessage(&msg);}

		if(msg.message == WM_QUIT)
			break;

		calcwave();
	}
	return msg.wParam;
}

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch(message)
	{
		case WM_DESTROY:
		{
			PostQuitMessage(0);
			return 0;
		} break;
		case WM_KEYDOWN:
		{
			switch (wParam)
			{
			case VK_NUMPAD4:
				_freq--;
				if(_freq < 1.0)
					_freq = 1.0;
				break;
			case VK_NUMPAD6:
				_freq++;
				break;
			case VK_NUMPAD8:
				_amp++;
				if(_amp > 200)
					_amp = 200;
				break;
			case VK_NUMPAD2:
				_amp--;
				if(_amp < 0)
					_amp = 0;
				break;
			case VK_SUBTRACT:
				_sTime++;
				if(_sTime > 50)
					_sTime = 50;
				break;
			case VK_ADD:
				_sTime--;
				if(_sTime < 10)
					_sTime = 10;
				break;
			case 0x48:
				MessageBoxA(NULL, "NUMPAD + : Increase speed\n"
					 "NUMPAD - : Decrease speed\n"
					 "NUMPAD 8 : Increase amplitude\n"
					 "NUMPAD 2 : Decrease amplitude\n"
					 "NUMPAD 4 : Increase frequency\n"
					 "NUMPAD 6 : Decrease frequency\n"
					 "\nChanges are small, hold the button",
					 "Help", MB_OK);
				break;
			}
			return 0;
		} break;
     }
     return DefWindowProc(hWnd, message, wParam, lParam);
 }

void calcwave()
{
	static const double _full = 2 * pi;
	static double _x = 0;

	_yc._one._y = (sin(_x)*_amp) + 300;

	_x += 1.0 / _freq;
	if (_x >= _full)
		_x -= _full;

	_amplitude = "Amplitude : " + convstr(_amp * 2) + " pixels";
	_frequency = "Frequency : " + convstr(_full * _freq) + " pixels";
	_speed = "Speed : " + convstr(_sTime);
	
	drawwave();
	
	TextOutA(hDC, 0, 0, _amplitude.c_str(), _amplitude.size());
	TextOutA(hDC, 0, 17, _frequency.c_str(), _frequency.size());
	TextOutA(hDC, 0, 34, _speed.c_str(), _speed.size());

	_yc._two._y = _yc._one._y;
}

void drawwave()
{
	MoveToEx(hDC, _yc._two._x, _yc._two._y, NULL);
	LineTo(hDC, _yc._one._x, _yc._one._y);
	ScrollWindow(hWnd, -1, 0, NULL, NULL);
	Sleep(_sTime);
}

std::string convstr(const int& t)
{
	std::stringstream itoa;
	itoa << t;
	return itoa.str();
}
guestgulkan (2942)
hint:
Read up on the ScrollWindow function - (you already use it in your code) - especially read about those last two parameters that you are currently setting to NULL .
closed account (zwA4jE8b)
thank you sir.

I am having a little trouble still,

I defined this rectangle area and added it to scroll window. The text no longer gets distorted because it is out of the rectangular area but now the drawn sine wave is scrolled as a solid chunk. Could you please give me an example of what I need to do here? I do not quite understand what I need for the lpClipRect parameter. The lpRect parameter seems pretty straightforward and I believe my current Rect structure is correct for that.

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const RECT rect = {0, 50, 600, 800};
.......
ScrollWindow(hWnd, -1, 0, &rect, NULL);
Last edited on
guestgulkan (2942)
Oh, I see what you mean - that is interesting!
I'm going to investigate..
closed account (zwA4jE8b)
thank you for your time and effort, let me know what you discover. I will also try to figure it out in the meantime
guestgulkan (2942)
OK - i'm a bit stuck getting the clip to work.
So I've taken the sensible way out.
I've gone back to scrolling the whole window,BUT move the display of the text from where it
was and into a seperate function.

So how does the new code below perform on your system?? 

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//Michael Ervin - Windows Sine Wave

#include <Windows.h>
#include <math.h>
#include <string>
#include <sstream>

#define screen_width 800
#define screen_height 600
#define pi 3.14159

struct _points
{
    int _x;
    int _y;
};

struct _ycoords
{
    _points _one;
    _points _two;
} _yc;

COLORREF blue = RGB(0, 0, 255);
HDC hDC;
HWND hWnd;
std::string _amplitude, _frequency, _speed;

double _freq = 50;
int _sTime = 30, _amp = 100;

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
void calcwave();
void drawwave();
void drawtext();//<<< **************************************
std::string convstr(const int& t);

int WINAPI WinMain(HINSTANCE hInstance,
                   HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine,
                   int nCmdShow)
{
    WNDCLASSEXA wc;

    ZeroMemory(&wc, sizeof(WNDCLASSEX));
    ZeroMemory(&_yc, sizeof(_yc));
    _yc._one._x = 600;
    _yc._two._x = 599;
    _yc._two._y = 300;

    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hIcon = (HICON)LoadImageA(NULL, "C:\\Visual Studio 2010\\Icons\\Smiley.ico", IMAGE_ICON, 0, 0, LR_LOADFROMFILE);
    wc.lpszClassName = "SineWave";

    RegisterClassExA(&wc);

    hWnd = CreateWindowExA(NULL,
                          "SineWave", "SineWave",
                          WS_SYSMENU,
                          0, 45,
                          screen_width, screen_height,
                          NULL, NULL,
                          hInstance,
                          NULL);

    ShowWindow(hWnd, nCmdShow);
    hDC = GetDC(hWnd);

    HPEN _Pen = CreatePen(PS_SOLID, 1, blue);
    SelectObject(hDC, _Pen);

    MSG msg;

    while(TRUE)
    {
        while(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
        {DispatchMessage(&msg);}

        if(msg.message == WM_QUIT)
            break;

        calcwave();
    }
    return msg.wParam;
}

LRESULT CALLBACK WindowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
        case WM_DESTROY:
        {
            PostQuitMessage(0);
            return 0;
        } break;
        case WM_KEYDOWN:
        {
            switch (wParam)
            {
            case VK_NUMPAD4:
                _freq--;
                if(_freq < 1.0)
                    _freq = 1.0;
                break;
            case VK_NUMPAD6:
                _freq++;
                break;
            case VK_NUMPAD8:
                _amp++;
                if(_amp > 200)
                    _amp = 200;
                break;
            case VK_NUMPAD2:
                _amp--;
                if(_amp < 0)
                    _amp = 0;
                break;
            case VK_SUBTRACT:
                _sTime++;
                if(_sTime > 50)
                    _sTime = 50;
                break;
            case VK_ADD:
                _sTime--;
                if(_sTime < 10)
                    _sTime = 10;
                break;
            case 0x48:
                MessageBoxA(NULL, "NUMPAD + : Increase speed\n"
                     "NUMPAD - : Decrease speed\n"
                     "NUMPAD 8 : Increase amplitude\n"
                     "NUMPAD 2 : Decrease amplitude\n"
                     "NUMPAD 4 : Increase frequency\n"
                     "NUMPAD 6 : Decrease frequency\n"
                     "\nChanges are small, hold the button",
                     "Help", MB_OK);
                break;
            }
            return 0;
        } break;
     }
     return DefWindowProc(hWnd, message, wParam, lParam);
 }



void calcwave()
{
    static const double _full = 2 * pi;
    static double _x = 0;

    _yc._one._y = (sin(_x)*_amp) + 300;

    _x += 1.0 / _freq;
    if (_x >= _full)
        _x -= _full;

    _amplitude = "Amplitude : " + convstr(_amp * 2) + " pixels";
    _frequency = "Frequency : " + convstr(_full * _freq) + " pixels";
    _speed = "Speed : " + convstr(_sTime);
    
    drawwave();
    
    
    //*******commented out this
    //TextOutA(hDC, 0, 0, _amplitude.c_str(), _amplitude.size());
    //TextOutA(hDC, 0, 17, _frequency.c_str(), _frequency.size());
    //TextOutA(hDC, 0, 34, _speed.c_str(), _speed.size());
    
    //We use a seperate function for drawing the text
    drawtext(); //call the drawtext function

    _yc._two._y = _yc._one._y;
}

void drawwave()
{
    const RECT rect = {0, 50, 600, 800};
    
    
    MoveToEx(hDC, _yc._two._x, _yc._two._y, NULL);
    LineTo(hDC, _yc._one._x, _yc._one._y);    
    
    ScrollWindow(hWnd, -1, 0, NULL,NULL );
    Sleep(_sTime);
}


//***********************************************
//DrawText function
//***********************************************
void drawtext()
{

    TextOutA(hDC, 0, 0, _amplitude.c_str(), _amplitude.size());
    TextOutA(hDC, 0, 17, _frequency.c_str(), _frequency.size());
    TextOutA(hDC, 0, 34, _speed.c_str(), _speed.size());
}

std::string convstr(const int& t)
{
    std::stringstream itoa;
    itoa << t;
    return itoa.str();
}
Last edited on
closed account (zwA4jE8b)
it works, but the same as before, if the text is not lined up at x-coordinate = 0, it also scrolls.
m4ster r0shi (2201)
Increase 600 here:

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const RECT rect = {0, 50, 600, 800};
//...
ScrollWindow(hWnd, -1, 0, &rect, NULL);

Last edited on
closed account (zwA4jE8b)
@m4ster r0shi
Pardon me, what do you mean exactly? your post looks identical to mine, so I am unclear as to what you are saying.
m4ster r0shi (2201)
You should increase 600. Try making it 800.

In fact, it should be -> const RECT rect = {0, 50, screen_width, screen_height};

See why here -> http://msdn.microsoft.com/en-us/library/dd162897(v=vs.85).aspx

Last edited on
closed account (zwA4jE8b)
oh wow, that is embarrassing. I confused the x and y values of the bottom right corner.
Thank you for correcting me.
closed account (zwA4jE8b)
thank you, works perfectly now.

Just for the sake of conversation.... is there a better method to use than Sleep?

I am using Sleep to keep the wave from drawing too fast. I know of timers but have not used them. Would a timer be better?
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