Broken MemDC Paint (Trying Alternatives) bkp

#include <vector>
#include <windows.h>
#include <fstream>
#include <string>
#include <commdlg.h>
#include <codecvt>
#include <algorithm>

using namespace std;

struct Brushstroke;
struct Eraserstroke;
HWND hWnd;
HINSTANCE hInst;

bool IsPointInCircle(int px, int py, int cx, int cy, int radius) {
    int distSq = (px - cx) * (px - cx) + (py - cy) * (py - cy);
    return distSq <= radius * radius;
}

bool IsPointInClientRect(HWND hwnd, int x, int y) {
    RECT rect;
    GetClientRect(hwnd, &rect);
    return (x >= 0 && x < rect.right&& y >= 0 && y < rect.bottom);
}

struct Brushstroke {
    int x;
    int y;
    int size;
    COLORREF color;
    unsigned long timestamp;

    void serialize(ofstream& outFile) const {
        outFile << "B " << x << " " << y << " " << size << " "
            << (int)GetRValue(color) << " "
            << (int)GetGValue(color) << " "
            << (int)GetBValue(color) << " "
            << timestamp << endl;
    }
};

struct Eraserstroke {
    int x;
    int y;
    int size;
    COLORREF color;
    unsigned long timestamp;

    void serialize(ofstream& outFile) const {
        outFile << "E " << x << " " << y << " " << size << " "
            << (int)GetRValue(color) << " "
            << (int)GetGValue(color) << " "
            << (int)GetBValue(color) << " "
            << timestamp << endl;
    }
};

std::vector<Brushstroke> storedBrushstrokes;
std::vector<Eraserstroke> storedEraserstrokes;

void RedrawStrokes();
void SaveDrawing(const string& filename);
void LoadDrawing(const string& filename);

POINT previousPoint;
HDC hdc, memDC;
HBITMAP memBitmap;

bool isPaintbrushSelected = true;
bool isDrawing = false;
bool isErasing = false;
bool isClearing = false;
bool isEraserSelected = false;
int brushSize = 10;

unsigned long currentTimestamp = 0;

void DrawBrush(HDC hdc, int x, int y, COLORREF color, unsigned long timestamp) {
    if (!IsPointInClientRect(hWnd, x, y)) return;

    for (const auto& eraserstroke : storedEraserstrokes) {
        if (eraserstroke.timestamp < timestamp &&
            IsPointInCircle(x, y, eraserstroke.x, eraserstroke.y, eraserstroke.size + brushSize)) {
            return; // Don't draw if erased
        }
    }

    HGDIOBJ originalBrush = SelectObject(hdc, CreateSolidBrush(color));
    HGDIOBJ originalPen = SelectObject(hdc, GetStockObject(NULL_PEN));
    Ellipse(hdc, x - brushSize, y - brushSize, x + brushSize, y + brushSize);
    DeleteObject(SelectObject(hdc, originalBrush));
    DeleteObject(SelectObject(hdc, originalPen));
}

void Erase(HDC hdc, int x, int y, int eraserSize, COLORREF color = RGB(255, 255, 255)) {
    if (!IsPointInClientRect(hWnd, x, y)) return;

    Eraserstroke newEraserstroke;
    newEraserstroke.x = x;
    newEraserstroke.y = y;
    newEraserstroke.size = eraserSize;
    newEraserstroke.color = color;
    newEraserstroke.timestamp = currentTimestamp++;
    storedEraserstrokes.push_back(newEraserstroke);

    RedrawStrokes();
}

void ClearDrawing(HWND hwnd) {
    RECT rect;
    GetClientRect(hwnd, &rect);
    HBRUSH hBrush = CreateSolidBrush(RGB(255, 255, 255));
    HDC hdc = GetDC(hwnd);
    FillRect(hdc, &rect, hBrush);
    FillRect(memDC, &rect, hBrush);
    ReleaseDC(hwnd, hdc);
    DeleteObject(hBrush);
    storedBrushstrokes.clear();
    storedEraserstrokes.clear();
    InvalidateRect(hwnd, NULL, FALSE);
    UpdateWindow(hwnd);
}

void DrawSmoothBrush(HDC hdc, int x, int y) {
    if (isDrawing && (isPaintbrushSelected || isEraserSelected)) {
        int numPoints = 3;
        POINT currentPoint = { x, y };
        for (int i = 1; i <= numPoints; i++) {
            float t = (float)i / (float)numPoints;
            int smoothX = (int)(previousPoint.x + t * (currentPoint.x - previousPoint.x));
            int smoothY = (int)(previousPoint.y + t * (currentPoint.y - previousPoint.y));
            if (isPaintbrushSelected) {
                unsigned long timestamp = currentTimestamp++;
                DrawBrush(hdc, smoothX, smoothY, RGB(255, 0, 0), timestamp);
                Brushstroke newBrushstroke;
                newBrushstroke.x = smoothX;
                newBrushstroke.y = smoothY;
                newBrushstroke.size = brushSize;
                newBrushstroke.color = RGB(255, 0, 0);
                newBrushstroke.timestamp = timestamp;
                storedBrushstrokes.push_back(newBrushstroke);
            }
            else if (isEraserSelected) {
                Erase(hdc, smoothX, smoothY, brushSize);
            }
        }
        previousPoint = currentPoint;
    }
}

void RedrawStrokes() {
    RECT rect;
    GetClientRect(hWnd, &rect);
    HBRUSH hBrush = CreateSolidBrush(RGB(255, 255, 255));
    FillRect(memDC, &rect, hBrush);
    DeleteObject(hBrush);

    for (const auto& brushstroke : storedBrushstrokes) {
        DrawBrush(memDC, brushstroke.x, brushstroke.y, brushstroke.color, brushstroke.timestamp);
    }

    for (const auto& eraserstroke : storedEraserstrokes) {
        Erase(memDC, eraserstroke.x, eraserstroke.y, eraserstroke.size, eraserstroke.color);
    }

    InvalidateRect(hWnd, NULL, FALSE);
    UpdateWindow(hWnd);
}

void SaveDrawing(const string& filename) {
    ofstream outFile(filename);
    if (outFile.is_open()) {
        outFile << storedBrushstrokes.size() << " " << storedEraserstrokes.size() << endl;

        for (const auto& brushstroke : storedBrushstrokes) {
            brushstroke.serialize(outFile);
        }

        for (const auto& eraserstroke : storedEraserstrokes) {
            eraserstroke.serialize(outFile);
        }

        outFile.close();
    }
}

void LoadDrawing(const string& filename) {
    ifstream inFile(filename);
    if (inFile.is_open()) {
        ClearDrawing(hWnd);

        int numBrushstrokes, numEraserstrokes;
        inFile >> numBrushstrokes >> numEraserstrokes;

        storedBrushstrokes.clear();
        storedBrushstrokes.reserve(numBrushstrokes);

        storedEraserstrokes.clear();
        storedEraserstrokes.reserve(numEraserstrokes);

        for (int i = 0; i < numBrushstrokes; ++i) {
            char type;
            Brushstroke brushstroke;
            int r, g, b;
            inFile >> type >> brushstroke.x >> brushstroke.y >> brushstroke.size >> r >> g >> b >> brushstroke.timestamp;
            brushstroke.color = RGB(r, g, b);
            storedBrushstrokes.push_back(brushstroke);
        }

        for (int i = 0; i < numEraserstrokes; ++i) {
            char type;
            Eraserstroke eraserstroke;
            int r, g, b;
            inFile >> type >> eraserstroke.x >> eraserstroke.y >> eraserstroke.size >> r >> g >> b >> eraserstroke.timestamp;
            eraserstroke.color = RGB(r, g, b);
            storedEraserstrokes.push_back(eraserstroke);
        }

        inFile.close();
        RedrawStrokes();
    }

    currentTimestamp = 0;
    for (const auto& brushstroke : storedBrushstrokes)
    {
        if (brushstroke.timestamp > currentTimestamp) {
            currentTimestamp = brushstroke.timestamp;
        }
    }
    for (const auto& eraserstroke : storedEraserstrokes) {
        if (eraserstroke.timestamp > currentTimestamp) {
            currentTimestamp = eraserstroke.timestamp;
        }
    }
    currentTimestamp++;
}

void SaveDrawingDialog(HWND hwnd) {
    OPENFILENAME ofn;
    wchar_t szFileName[MAX_PATH] = L"";

    ZeroMemory(&ofn, sizeof(ofn));
    ofn.lStructSize = sizeof(ofn);
    ofn.hwndOwner = hwnd;
    ofn.lpstrFilter = L"Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0";
    ofn.lpstrFile = szFileName;
    ofn.nMaxFile = MAX_PATH;
    ofn.Flags = OFN_EXPLORER | OFN_OVERWRITEPROMPT;
    ofn.lpstrDefExt = L"txt";

    if (GetSaveFileName(&ofn)) {
        std::wstring_convert < std::codecvt_utf8 < wchar_t>> converter;
        std::string filenameStr = converter.to_bytes(szFileName);
        SaveDrawing(filenameStr);
        MessageBox(hwnd, L"Save Complete", L"Doodle App", MB_OK | MB_ICONINFORMATION);
    }
}

void LoadDrawingDialog(HWND hwnd) {
    OPENFILENAME ofn;
    wchar_t szFileName[MAX_PATH] = L"";

    ZeroMemory(&ofn, sizeof(ofn));
    ofn.lStructSize = sizeof(ofn);
    ofn.hwndOwner = hwnd;
    ofn.lpstrFilter = L"Text Files (*.txt)\0*.txt\0All Files (*.*)\0*.*\0";
    ofn.lpstrFile = szFileName;
    ofn.nMaxFile = MAX_PATH;
    ofn.Flags = OFN_EXPLORER | OFN_FILEMUSTEXIST;

    if (GetOpenFileName(&ofn)) {
        std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
        std::string filenameStr = converter.to_bytes(szFileName);
        LoadDrawing(filenameStr);
    }
}

void SanitizeAndSaveDrawing(const string& filename) {
    ofstream outFile(filename);
    if (outFile.is_open()) {
        RECT rect;
        GetClientRect(hWnd, &rect);

        vector<Brushstroke> validBrushstrokes;
        for (const auto& brushstroke : storedBrushstrokes) {
            if (IsPointInClientRect(hWnd, brushstroke.x, brushstroke.y)) {
                validBrushstrokes.push_back(brushstroke);
            }
        }

        vector<Eraserstroke> validEraserstrokes;
        for (const auto& eraserstroke : storedEraserstrokes) {
            if (IsPointInClientRect(hWnd, eraserstroke.x, eraserstroke.y)) {
                validEraserstrokes.push_back(eraserstroke);
            }
        }

        outFile << validBrushstrokes.size() << " " << validEraserstrokes.size() << endl;

        for (const auto& brushstroke : validBrushstrokes) {
            brushstroke.serialize(outFile);
        }

        for (const auto& eraserstroke : validEraserstrokes) {
            eraserstroke.serialize(outFile);
        }

        outFile.close();
    }
}

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
    switch (uMsg) {
    case WM_CREATE:
    {
        hWnd = hwnd;
        RECT rect;
        GetClientRect(hwnd, &rect);
        HDC hdc = GetDC(hwnd);
        memDC = CreateCompatibleDC(hdc);
        memBitmap = CreateCompatibleBitmap(hdc, rect.right - rect.left, rect.bottom - rect.top);
        SelectObject(memDC, memBitmap);
        ReleaseDC(hwnd, hdc);
        HBRUSH hBrush = CreateSolidBrush(RGB(255, 255, 255));
        FillRect(memDC, &rect, hBrush);
        DeleteObject(hBrush);
        isPaintbrushSelected = true;
        LoadDrawing("drawing.txt");
    }
    break;
    case WM_KEYDOWN:
        if (wParam == VK_ADD) {
            brushSize += 5;
        }
        else if (wParam == VK_SUBTRACT) {
            if (brushSize > 5) {
                brushSize -= 5;
            }
        }
        else if (wParam == 0x43) { // 'C' key
            if (!(GetKeyState(VK_CONTROL) & 0x8000)) {
                ClearDrawing(hwnd);
            }
        }
        else if (wParam == 0x50) {
            isPaintbrushSelected = true;
            isEraserSelected = false;
        }
        else if (wParam == 0x45) {
            isEraserSelected = true;
            isPaintbrushSelected = false;
        }
        else if (wParam == 'S' && (GetKeyState(VK_CONTROL) & 0x8000)) {
            SaveDrawingDialog(hwnd);
        }
        else if (wParam == 'O' && (GetKeyState(VK_CONTROL) & 0x8000)) {
            LoadDrawingDialog(hwnd);
        }
        break;
    case WM_LBUTTONDOWN:
        if (isPaintbrushSelected || isEraserSelected) {
            previousPoint.x = LOWORD(lParam);
            previousPoint.y = HIWORD(lParam);
        }
        isDrawing = true;
        break;
    case WM_LBUTTONUP:
        isDrawing = false;
        break;
    case WM_MOUSEMOVE:
        if (isDrawing && isPaintbrushSelected) {
            int x = LOWORD(lParam);
            int y = HIWORD(lParam);
            DrawSmoothBrush(memDC, x, y);
            InvalidateRect(hwnd, NULL, FALSE);
            if (IsPointInClientRect(hWnd, x, y)) {
                Brushstroke newBrushstroke;
                newBrushstroke.x = x;
                newBrushstroke.y = y;
                newBrushstroke.size = brushSize;
                newBrushstroke.color = RGB(255, 0, 0);
                newBrushstroke.timestamp = currentTimestamp++;
                storedBrushstrokes.push_back(newBrushstroke);
            }
        }
        else if (isDrawing && isEraserSelected) {
            int x = LOWORD(lParam);
            int y = HIWORD(lParam);
            Erase(memDC, x, y, brushSize);
            Eraserstroke newEraserstroke;
            newEraserstroke.x = x;
            newEraserstroke.y = y;
            newEraserstroke.size = brushSize;
            newEraserstroke.color = RGB(255, 255, 255);
            newEraserstroke.timestamp = currentTimestamp++;
            storedEraserstrokes.push_back(newEraserstroke);
        }
        break;
    case WM_SIZE:
    {
        static bool isMinimized = false;
        if (wParam == SIZE_MINIMIZED)
        {
            isMinimized = true;
        }
        else if (wParam == SIZE_MAXIMIZED || wParam == SIZE_RESTORED)
        {
            if (isMinimized)
            {
                isMinimized = false;
            }
            InvalidateRect(hwnd, NULL, TRUE);
        }
        RECT rect;
        GetClientRect(hwnd, &rect);
        if (memDC)
        {
            DeleteDC(memDC);
            DeleteObject(memBitmap);
        }
        HDC hdc = GetDC(hwnd);
        memDC = CreateCompatibleDC(hdc);
        memBitmap = CreateCompatibleBitmap(hdc, rect.right - rect.left, rect.bottom - rect.top);
        SelectObject(memDC, memBitmap);
        ReleaseDC(hwnd, hdc);
        HBRUSH hBrush = CreateSolidBrush(RGB(255, 255, 255));
        FillRect(memDC, &rect, hBrush);
        DeleteObject(hBrush);
        RedrawStrokes();
    }
    break;

    case WM_PAINT:
    {
        PAINTSTRUCT ps;
        HDC hdc = BeginPaint(hwnd, &ps);
        RECT rect;
        GetClientRect(hwnd, &rect);
        BitBlt(hdc, 0, 0, rect.right - rect.left, rect.bottom - rect.top, memDC, 0, 0, SRCCOPY);
        EndPaint(hwnd, &ps);
    }
    break;

    case WM_DESTROY:
        SanitizeAndSaveDrawing("drawing.txt");
        DeleteObject(memBitmap);
        DeleteDC(memDC);
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hwnd, uMsg, wParam, lParam);
    }
    return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
    WNDCLASSEX wc = {};
    wc.cbSize = sizeof(wc);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WindowProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszClassName = L"MyClass";
    RegisterClassEx(&wc);
    HWND hwnd = CreateWindowEx(
        0, L"MyClass", L"Doodle App",
        WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600,
        NULL, NULL, hInstance, NULL
    );
    if (hwnd == NULL) {
        return 0;
    }
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}