#include <windows.h>

#include <d2d1.h>

#include <d2d1helper.h>

#include <dwrite.h>

#pragma comment(lib, "dwrite.lib")

#pragma comment(lib, "d2d1.lib")

HINSTANCE g_hinst;

HWND g_hwnd;

ID2D1Factory * g_factory;

ID2D1HwndRenderTarget * g_render_target;

ID2D1SolidColorBrush  * g_brush;

IDWriteFactory * g_write_factory;

IDWriteTextFormat * g_text_format;

ID2D1GradientStopCollection * g_gradient_stop_collection;

ID2D1LinearGradientBrush  * g_linear_gradient_brush;

ID2D1RadialGradientBrush * g_radial_gradient_brush;

bool AppInit()

{

	D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &g_factory);

	RECT rc;

	GetClientRect(g_hwnd, &rc);

	g_factory->CreateHwndRenderTarget(

		D2D1::RenderTargetProperties(),

		D2D1::HwndRenderTargetProperties(g_hwnd, D2D1::SizeU(rc.right - rc.left, rc.bottom - rc.top)	),

		&g_render_target);

	g_render_target->CreateSolidColorBrush(D2D1::ColorF(D2D1::ColorF::WhiteSmoke), &g_brush);

	// Init Font

	DWriteCreateFactory(DWRITE_FACTORY_TYPE_SHARED,__uuidof(g_write_factory),reinterpret_cast<IUnknown **>(&g_write_factory));

	g_write_factory->CreateTextFormat(L"Arial Block", NULL, DWRITE_FONT_WEIGHT_NORMAL,

		DWRITE_FONT_STYLE_NORMAL, DWRITE_FONT_STRETCH_NORMAL, 40, L"",&g_text_format);

	// Create Gradient Stops

	D2D1_GRADIENT_STOP gradient_stops[3];

	gradient_stops[0].color = D2D1::ColorF(D2D1::ColorF::YellowGreen);

	gradient_stops[0].position = 0.0f;

	gradient_stops[1].color = D2D1::ColorF(D2D1::ColorF::ForestGreen);

	gradient_stops[1].position = 0.5f;

	gradient_stops[2].color = D2D1::ColorF(D2D1::ColorF::Green);

	gradient_stops[2].position = 1.0f;

	// Create Interface

	g_render_target->CreateGradientStopCollection(gradient_stops, 3, &g_gradient_stop_collection);

	// Create Linear Gradient Brush

	g_render_target->CreateLinearGradientBrush(

	D2D1::LinearGradientBrushProperties(D2D1::Point2F(0,0), D2D1::Point2F(600,600)),

		g_gradient_stop_collection, &g_linear_gradient_brush);

	g_render_target->CreateRadialGradientBrush(

		D2D1::RadialGradientBrushProperties(D2D1::Point2F(500,500),D2D1::Point2F(),1000.0f,1000.0f),

		g_gradient_stop_collection,&g_radial_gradient_brush);

	return true;

}

void OnSize(LPARAM lparam)

{

	if(g_render_target)

		g_render_target->Resize(D2D1::SizeU(LOWORD(lparam),HIWORD(lparam)));

}

void OnPaint()

{

	if(!g_render_target)

		return;

	g_render_target->BeginDraw();

	// Clear Background

	g_render_target->Clear(D2D1::ColorF(0.63, 0.84, 0.00)); 

	// Draw Ellipse

    D2D1_SIZE_F size = g_render_target->GetSize();

    D2D1_ELLIPSE ellipse;

    ellipse.point = D2D1::Point2F(size.width/2.0, size.height/2.0);

    ellipse.radiusX = 280;

    ellipse.radiusY = 100;

	g_render_target->FillEllipse(&ellipse, g_radial_gradient_brush);

	//g_render_target->FillEllipse(&ellipse, g_linear_gradient_brush); 

	// Draw Text

	const wchar_t * text = L"Direct2D Gradient Brush";

	g_render_target->DrawText(text, wcslen(text),

		g_text_format,

		D2D1::RectF(100, 190, size.width, size.height),

		g_brush);

	g_render_target->EndDraw();

}

void OnDestroy()

{

	g_linear_gradient_brush->Release();

	g_radial_gradient_brush->Release();

	g_gradient_stop_collection->Release();

	g_text_format->Release();

	g_write_factory->Release();

	g_brush->Release();

	g_render_target->Release();

	g_factory->Release();

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)

{

	switch(msg)

	{

	case WM_PAINT:

		OnPaint();

		break;

	case WM_SIZE:

		OnSize(lparam);

		break;

	case WM_DESTROY:

		OnDestroy();

		PostQuitMessage(0);

		break;

	default:

		return DefWindowProc(hwnd, msg, wparam, lparam);

	}

	return 0;

}

int WINAPI WinMain(HINSTANCE hinst, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)

{

	WNDCLASSEX wc;

	MSG msg;  

	memset(&wc,0,sizeof(wc));

	wc.cbSize = sizeof(WNDCLASSEX);

	wc.lpfnWndProc = WndProc;

	wc.hInstance = hinst;

	wc.hCursor = LoadCursor(NULL, IDC_ARROW);

	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);

	wc.lpszClassName = "WindowClass";

	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);

	wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION); 

	if(!RegisterClassEx(&wc))

	{

		MessageBox(NULL, "Window Registration Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);

		return 0;

	}

	g_hinst = hinst;

	g_hwnd = CreateWindowEx(WS_EX_CLIENTEDGE,"WindowClass","Direct2D Demo",WS_VISIBLE|WS_OVERLAPPEDWINDOW,

		CW_USEDEFAULT,

		CW_USEDEFAULT,

		640,

		480,

		NULL, NULL, hinst, NULL);

	if(g_hwnd == NULL)

	{

		MessageBox(NULL, "Window Creation Failed!","Error!",MB_ICONEXCLAMATION|MB_OK);

		return 0;

	}

	if(!AppInit())

	{

		MessageBox(NULL, "Application Initialisation Failed !","Error",MB_ICONEXCLAMATION|MB_OK);

		return 0;

	}

	while(GetMessage(&msg, NULL, 0, 0) > 0)

	{

		TranslateMessage(&msg);

		DispatchMessage(&msg);

	}

	return msg.wParam;

}