Related
To change the static's control color and width, I did process the WM_NCPAINT message, but it's not working properly:
the text isn't properly displayed. Should I draw it in this message? When I call SetWindowText(), the new text is properly set, but I still have the issue #2.
after a call to SetWindowText(), the text is set, but the border differs, it's smaller than the one I've draw in the WM_NCPAINT message.
Here's how I'm handling WM_NCPAINT:
case WM_NCPAINT:
{
PAINTSTRUCT ps;
HDC dc = BeginPaint(hwnd, &ps);
RECT rt = {0};
GetClientRect(hwnd, &rt);
HPEN pen = CreatePen(PS_SOLID, 3, RGB(255, 0, 0));
HPEN holdPen = SelectObject(dc, pen);
DrawBorder(dc, &rt);
SelectObject(dc, holdPen);
EndPaint(hwnd, &ps);
DeleteObject(pen);
pen = NULL;
return 0;
}
When the application starts, the static control border looks like the one I've draw at WM_NCPAINT:
But once I call SetWindowText(), for example, from a button click, it looks like this:
What am I missing?
Here's full code:
#pragma comment(lib, "user32.lib")
#pragma comment(lib, "Comctl32.lib")
#pragma comment(lib, "Gdi32.lib")
#define WIN32_LEAN_AND_MEAN
#define UNICODE
#define _UNICODE
#include <windows.h>
#include <Commctrl.h>
#include <crtdbg.h>
#include <strsafe.h>
#include <string.h>
#include <assert.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
void EnableVisualStyles2(void);
LRESULT CALLBACK ButtonProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
void SetDefaultFont(HWND hwnd);
void DrawLine(HDC hdc, LONG x1, LONG y1, LONG x2, LONG y2);
void DrawBorder(HDC hdc, RECT *rect);
HFONT getSystemDefaultFont(void);
WNDPROC oldButtonProc;
HINSTANCE ghInstance;
HFONT hDefaultFont;
HWND btn, btn2;
enum
{
BTN_ID = 10,
BTN2_ID,
};
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
PWSTR pCmdLine, int nCmdShow)
{
MSG msg = {0};
HWND hwnd;
WNDCLASSW wc = {0};
wc.lpszClassName = L"Window";
wc.hInstance = hInstance;
wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
wc.lpfnWndProc = WndProc;
wc.hCursor = LoadCursor(0, IDC_ARROW);
EnableVisualStyles2();
if(!RegisterClass(&wc)) {
return -1;
}
int width = 540;
int height = 460;
int screenWidth = GetSystemMetrics(SM_CXSCREEN);
int screenHeight = GetSystemMetrics(SM_CYSCREEN);
int cx = (screenWidth - width) / 2;
int cy = (screenHeight - height) / 2;
hwnd = CreateWindowW(wc.lpszClassName, L"Window",
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
cx, cy, width, height, NULL, NULL,
hInstance, NULL);
ghInstance = hInstance;
while (GetMessage(&msg, NULL, 0, 0))
{
if (!IsDialogMessage(hwnd, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
DeleteObject(hDefaultFont);
return (int) msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CREATE:
{
btn =
CreateWindow(L"static", L"+",
WS_VISIBLE | WS_CHILD | WS_TABSTOP |
SS_NOTIFY | SS_CENTER | SS_CENTERIMAGE,
15, 25, 50, 50,
hwnd, (HMENU) BTN_ID, NULL, NULL);
SetDefaultFont(btn);
oldButtonProc = (WNDPROC) SetWindowLongPtr(btn,
GWLP_WNDPROC,
(LONG_PTR) ButtonProc);
btn2 =
CreateWindow(L"Button", L"Click me!",
WS_VISIBLE | WS_CHILD | WS_TABSTOP,
15, 100, 70, 25,
hwnd, (HMENU) BTN2_ID,
NULL, NULL);
SetDefaultFont(btn2);
}
break;
case WM_COMMAND:
{
switch(LOWORD(wParam))
{
case BTN_ID:
{
//InvalidateRect(btn, NULL, TRUE);
if(IsWindowVisible(btn2))
{
SetWindowText(btn, L"+");
ShowWindow(btn2, SW_HIDE);
}
else
{
SetWindowText(btn, L"-");
ShowWindow(btn2, SW_SHOW);
}
}
break;
case BTN2_ID:
{
InvalidateRect(btn, NULL, TRUE);
//SetWindowText(btn, L"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa0");
}
break;
}
}
break;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, msg, wParam, lParam);
}
LRESULT CALLBACK ButtonProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_NCPAINT:
{
PAINTSTRUCT ps;
HDC dc = BeginPaint(hwnd, &ps);
RECT rt = {0};
GetClientRect(hwnd, &rt);
HPEN pen = CreatePen(PS_SOLID, 3, RGB(255, 0, 0));
HPEN holdPen = SelectObject(dc, pen);
DrawBorder(dc, &rt);
SelectObject(dc, holdPen);
EndPaint(hwnd, &ps);
DeleteObject(pen);
pen = NULL;
return 0;
}
}
return CallWindowProc(oldButtonProc, hwnd, msg, wParam, lParam);
}
void EnableVisualStyles2(void)
{
TCHAR dir[MAX_PATH] = {0};
GetSystemDirectory(dir, sizeof(dir) / sizeof(*dir));
ACTCTX actCtx = {0};
actCtx.cbSize = sizeof(ACTCTX);
actCtx.dwFlags = ACTCTX_FLAG_RESOURCE_NAME_VALID |
ACTCTX_FLAG_SET_PROCESS_DEFAULT |
ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID;
actCtx.lpSource = L"shell32.dll";
actCtx.lpAssemblyDirectory = dir;
actCtx.lpResourceName = (LPCTSTR) 124;
ULONG_PTR cookie = FALSE;
HANDLE h = CreateActCtx(&actCtx);
assert(h != INVALID_HANDLE_VALUE);
assert(ActivateActCtx(h, &cookie));
}
HFONT getSystemDefaultFont(void)
{
if(!hDefaultFont)
{
// get system default font
NONCLIENTMETRICS ncm;
ncm.cbSize = sizeof(NONCLIENTMETRICS);
SystemParametersInfo(SPI_GETNONCLIENTMETRICS, sizeof(NONCLIENTMETRICS), &ncm, 0);
hDefaultFont = CreateFontIndirect(&ncm.lfMessageFont);
}
return hDefaultFont;
}
void SetDefaultFont(HWND hwnd)
{
SendMessage(hwnd, WM_SETFONT, (WPARAM)getSystemDefaultFont(), FALSE);
}
void DrawLine(HDC hdc, LONG x1, LONG y1, LONG x2, LONG y2)
{
MoveToEx(hdc, x1, y1, NULL);
LineTo(hdc, x2, y2);
}
void DrawBorder(HDC hdc, RECT *rect)
{
DrawLine(hdc, rect->left, rect->top, rect->left, rect->bottom);
DrawLine(hdc, rect->left, rect->top, rect->right, rect->top);
DrawLine(hdc, rect->right, rect->top, rect->right, rect->bottom);
DrawLine(hdc, rect->left, rect->bottom, rect->right, rect->bottom);
}
Your static control does not have a transparent background, so when you call the SetWindowText function, the static control partially covers the external lines you draw.
You can add the following code in WndProc:
case WM_CTLCOLORSTATIC:
{
HDC hdcStatic = (HDC)wParam;
SetBkMode(hdcStatic, TRANSPARENT);
return (LRESULT)GetStockObject(NULL_BRUSH);
}
But this code tells the static control to draw the text without a background color and not to repaint the background. So the new text is drawn on top of the old text instead of on a fresh background.You can refer to this thread to try to solve it.
Of course, you can also extend the boundary of the straight line when drawing a straight line (you do not need to process the WM_CTLCOLORSTATIC message), as shown in the following code:
void DrawBorder(HDC hdc, RECT* rect)
{
DrawLine(hdc, rect->left - 3, rect->top - 3, rect->left - 3, rect->bottom + 3) ;
DrawLine(hdc, rect->left - 3, rect->top - 3, rect->right + 3, rect->top - 3);
DrawLine(hdc, rect->right + 3, rect->top - 3, rect->right + 3, rect->bottom + 3);
DrawLine(hdc, rect->left - 3, rect->bottom + 3, rect->right + 3, rect->bottom + 3);
}
This is the modified effect:
I tried to color customize menu items (pure WinAPI). But there is a line in the menu bar which does not draw with MenuInfo.hbrBack color. If the mouse cursor hover above items a part of this line is redrawn. But if I resize the window the line will return. And in the area of menu bar where no items the line drawn constantly. How can I draw over this annoying line?
#include <windows.h>
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
struct
{
COLORREF text = RGB(200, 200, 250);
COLORREF clientBorder = RGB(120, 0, 0);
COLORREF clientBackground = RGB(100, 100, 100);
COLORREF itemBorder = RGB(0, 0, 255);
COLORREF itemBackground = RGB(0, 120, 0);
COLORREF pink = RGB(255, 0, 255);
} colorTheme;
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst, LPSTR lpCmdLine, int nCmdShow)
{
MSG msg;
WNDCLASSEX wc;
wc.cbSize = sizeof(wc);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WndProc;
wc.lpszMenuName = NULL;
wc.lpszClassName = "MainWindow";
wc.cbWndExtra = NULL;
wc.cbClsExtra = NULL;
wc.hIcon = LoadIcon(NULL, IDI_WINLOGO);
wc.hIconSm = LoadIcon(NULL, IDI_WINLOGO);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = CreateSolidBrush(colorTheme.clientBackground);
wc.hInstance = hInst;
RegisterClassEx(&wc);
HWND hMainWnd = CreateWindow(
"MainWindow",
"MainWindow",
WS_OVERLAPPEDWINDOW,
100, 100, 450, 120,
(HWND)NULL, NULL, HINSTANCE(hInst), NULL);
HMENU hMenu = CreateMenu();
HMENU hMenuSub1 = CreatePopupMenu();
HMENU hMenuSub2 = CreatePopupMenu();
HMENU hMenuSub3 = CreatePopupMenu();
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub1, "SubMenu1");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item01");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item02");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item03");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item04");
AppendMenu(hMenuSub1, MF_OWNERDRAW, 0, "Item05");
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub2, "SubMenu2");
AppendMenu(hMenu, MF_OWNERDRAW | MF_POPUP, (UINT)hMenuSub3, "SubMenu3");
MENUINFO menuInfo;
menuInfo.cbSize = sizeof(menuInfo);
menuInfo.fMask = MIM_BACKGROUND;
menuInfo.hbrBack = CreateSolidBrush(colorTheme.pink);
SetMenuInfo(hMenu, &menuInfo);
SetMenu(hMainWnd, hMenu);
ShowWindow(hMainWnd, nCmdShow);
while (GetMessage(&msg, NULL, NULL, NULL)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg) {
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hDC = BeginPaint(hWnd, &ps);
HFONT hApplicationFont;
LOGFONT applicationFont;
applicationFont.lfHeight = 16;
applicationFont.lfWidth = 6;
applicationFont.lfEscapement = 0;
applicationFont.lfOrientation = 0;
applicationFont.lfWeight = FW_NORMAL;
applicationFont.lfItalic = FALSE;
applicationFont.lfUnderline = FALSE;
applicationFont.lfStrikeOut = FALSE;
applicationFont.lfCharSet = DEFAULT_CHARSET;
applicationFont.lfOutPrecision = OUT_DEFAULT_PRECIS;
applicationFont.lfClipPrecision = CLIP_DEFAULT_PRECIS;
applicationFont.lfQuality = ANTIALIASED_QUALITY;
applicationFont.lfPitchAndFamily = DEFAULT_PITCH;
strcpy_s(applicationFont.lfFaceName, "Arial");
hApplicationFont = CreateFontIndirectA(&applicationFont);
SelectObject(hDC, hApplicationFont);
SelectObject(hDC, GetStockObject(DC_PEN));
SetDCPenColor(hDC, colorTheme.clientBorder);
SelectObject(hDC, GetStockObject(DC_BRUSH));
SetDCBrushColor(hDC, colorTheme.clientBackground);
RECT clientRect;
GetClientRect(hWnd, &clientRect);
Rectangle(hDC, 0, 0, clientRect.right, clientRect.bottom);
EndPaint(hWnd, &ps);
break;
}
case WM_MEASUREITEM:
{
LPMEASUREITEMSTRUCT itemStruct = (LPMEASUREITEMSTRUCT)lParam;
const char* str = (const char*)(itemStruct->itemData);
SIZE strSize;
HDC hDC = GetDC(hWnd);
GetTextExtentPoint32(hDC, str, lstrlen(str), &strSize);
itemStruct->itemWidth = strSize.cx;
itemStruct->itemHeight = 30;
ReleaseDC(hWnd, hDC);
return TRUE;
break;
}
case WM_DRAWITEM:
{
LPDRAWITEMSTRUCT itemStruct = (LPDRAWITEMSTRUCT)lParam;
HDC hDC = itemStruct->hDC;
SelectObject(hDC, GetStockObject(DC_PEN));
SetDCPenColor(hDC, colorTheme.itemBorder);
SelectObject(hDC, GetStockObject(DC_BRUSH));
SetDCBrushColor(hDC, colorTheme.itemBackground);
SetTextColor(hDC, colorTheme.text);
SetBkMode(hDC, TRANSPARENT);
Rectangle(hDC, itemStruct->rcItem.left,
itemStruct->rcItem.top,
itemStruct->rcItem.right,
itemStruct->rcItem.bottom + 1);
DrawText(hDC, (const char*)(itemStruct->itemData), -1, &(itemStruct->rcItem), DT_SINGLELINE | DT_CENTER | DT_VCENTER);
break;
}
case WM_DESTROY:
{
PostQuitMessage(NULL);
break;
}
default:
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
return NULL;
}
It seems to be part of the non-client area of the window. If that's the case then to paint there you need to handle WM_NCPAINT.
It is a single pixel line above the window's client area, so for example if I add the following code to your program I can paint it in red.
// ... in the WNDPROC
case WM_NCPAINT:
{
auto result = DefWindowProc(hWnd, WM_NCPAINT, wParam, lParam);
HDC hdc = GetWindowDC(hWnd);
RECT r = GetNonclientMenuBorderRect(hWnd);
HBRUSH red = CreateSolidBrush(RGB(255, 0, 0));
FillRect(hdc, &r, red);
DeleteObject(red);
ReleaseDC(hWnd, hdc);
return result;
}
// ... elsewhere
RECT MapRectFromClientToWndCoords(HWND hwnd, const RECT& r)
{
RECT wnd_coords = r;
// map to screen
MapWindowPoints(hwnd, NULL, reinterpret_cast<POINT*>(&wnd_coords), 2);
RECT scr_coords;
GetWindowRect(hwnd, &scr_coords);
// map to window coords by substracting the window coord origin in
// screen coords.
OffsetRect(&wnd_coords, -scr_coords.left, -scr_coords.top);
return wnd_coords;
}
RECT GetNonclientMenuBorderRect(HWND hwnd)
{
RECT r;
GetClientRect(hwnd, &r);
r = MapRectFromClientToWndCoords(hwnd, r);
int y = r.top - 1;
return {
r.left,
y,
r.right,
y+1
};
}
Now an issue with the above code is that it is over-painting the rectangle after the default non-client painting is done. In theory this could flicker; in practice I don't notice a flicker. If it did flicker, however, a safer way to do this would be to modify the WPARAM you pass to DefWindowProc(hWnd, WM_NCPAINT, ... ) such that it is the handle to a region that is the region passed to WM_NCPAINT minus the rectangle you want to paint. This doesnt seem necessary to me, for whatever reason.
If you are using themes / visual styles, which pretty much everything is nowadays, you can't override a lot of the menu styling without using a workaround like https://github.com/adzm/win32-custom-menubar-aero-theme which also uses the same approach to get rid of the white line. Note that you will need to handle this in WM_NCPAINT and WM_NCACTIVATE.
On Windows, I'm trying to use CEF (Chromium Embedded Framework) to create a window application with parent window to be transparent and its child window to be opaque (I want to have a rounded corner and an arrow pointing to the status bar in the child window). Something similar to:
I tried to use SetLayeredWindowAttributes to make the parent window transparent but it also makes the child window transparent. Is there a way to make this happen on Windows?
SetLayeredWindowAttributes needs a color for transparency. Make sure the transparency color is not used by the child window. You can pick a random color, for example RGB(255, 0, 254) and assume the child window is not using it.
If you have no control over the child window, and you can't be sure what colors it might use, then SetWindowRgn is another option to create non-rectangular windows.
The example below shows how to set the region such that the corners are round with a triangle on top.
You can use GDI+ to gain more flexibility for drawing the region, and for anti-aliasing effect so that the borders look more smooth.
#include <Windows.h>
int triangle_height = 30;
int corner_size = 20;
int caption_height = 60;
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
switch(msg)
{
case WM_CREATE:
{
//create a child button for testing
CreateWindowW(L"BUTTON", L"Close", WS_CHILD | WS_VISIBLE,
10, caption_height + 10, 100, 30,
hwnd, HMENU(100), GetModuleHandle(NULL), NULL);
RECT rc;
GetClientRect(hwnd, &rc);
//create a triangle region
int w = rc.right;
int h = rc.bottom;
int z = triangle_height;
POINT pt[3];
pt[0] = { w / 2, 0 };
pt[1] = { w / 2 - z, z };
pt[2] = { w / 2 + z, z };
HRGN htri = CreatePolygonRgn(pt, 3, WINDING);
//create a round rectangle region
HRGN hrgn = CreateRoundRectRgn(0, z, w, h - z, corner_size, corner_size);
//combine the triangle with round rectangle
CombineRgn(hrgn, htri, hrgn, RGN_OR);
//set the new region
SetWindowRgn(hwnd, hrgn, TRUE);
DeleteObject(htri);
DeleteObject(hrgn);
return 0;
}
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hwnd, &ps);
RECT rc = ps.rcPaint;
//we don't have a standard title bar, paint one here:
rc.bottom = caption_height;
SetDCBrushColor(hdc, RGB(80, 80, 80));
FillRect(hdc, &rc, (HBRUSH)GetStockObject(DC_BRUSH));
//paint the background
rc = ps.rcPaint;
rc.top = caption_height;
SetDCBrushColor(hdc, RGB(240, 240, 240));
FillRect(hdc, &rc, (HBRUSH)GetStockObject(DC_BRUSH));
//use FrameRgn to paint a border around the region
HRGN hrgn = CreateRectRgn(0, 0, 0, 0);
GetWindowRgn(hwnd, hrgn);
SetDCBrushColor(hdc, RGB(128, 128, 128));
FrameRgn(hdc, hrgn, (HBRUSH)GetStockObject(DC_BRUSH), 1, 1);
DeleteObject(hrgn);
EndPaint(hwnd, &ps);
return 0;
}
case WM_NCHITTEST:
{
//we don't have a standard title-bar
//respond to our custome title-bar manually:
POINT pt;
GetCursorPos(&pt);
ScreenToClient(hwnd, &pt);
if(pt.y < caption_height)
return HTCAPTION;
break;
}
case WM_COMMAND:
if(HIWORD(wparam) == BN_CLICKED)
if(LOWORD(wparam) == 100)
SendMessage(hwnd, WM_CLOSE, 0, 0);
break;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd, msg, wparam, lparam);
}
int APIENTRY wWinMain(HINSTANCE hInstance, HINSTANCE, LPTSTR, int)
{
WNDCLASSEXW wcex = { sizeof(wcex) };
wcex.style = CS_DROPSHADOW;
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = NULL;
wcex.lpszClassName = L"classname";
RegisterClassExW(&wcex);
CreateWindowW(wcex.lpszClassName, L"Test", WS_VISIBLE | WS_POPUP,
200, 200, 600, 400, 0, 0, hInstance, 0);
MSG msg;
while(GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}
what is the proper way of implementing custom rounded border for EDIT control in pure WinAPI (no MFC)? I need an edit with border like this:
Should I subclass edit control and do custom painting in WM_NCPAINT or something like that?
I guess you have two options:
As you said, you could sub-class and override WM_NCPAINT, etc to provide your own non-client area
Alternatively, you could simply turn off the border styles on the edit control and make the parent window responsible for drawing the frame.
With option #1, you would need to override WM_NCCALCSIZE to make the non-client area of the edit control larger (i.e. make the client area smaller), and then WM_NCPAINT to render your custom frame. You may also need to handle WM_NCHITTEST. And of course you'd need to make the control itself physically larger to account for the extra frame thickness.
It depends on your application design and how many controls like this you wish to use, but if it were me I would go with option #2. Modifying the standard drawing behaviour of system controls, many of which have decades of accumulated kludges and compatibility fixes attached to them, is often not as easy as you might expect.
If you make sure the WS_BORDER and WS_EX_CLIENTEDGE styles aren't set on the edit control, it will have no visible border of its own. Then all you have to do is have the parent window, when processing WM_PAINT, draw the frame around it. Make sure you set the WS_CLIPCHILDREN style on the parent window so that your custom drawing doesn't overwrite the edit control.
Either path would probably work in the end though so it's up to you which way you go.
This is an implementation that works for me.
It subclass the "EDIT" class control and replaces the WM_NCPAINT handler to draw a rectangle with rounded corners for all edit boxes with the WS_BORDER or WS_EX_CLIENTEDGE style. It draws the border on the parent DC.
The diameter of the corner is now fixed (10), I guess that should depend on the font size ...
Thanks to Darren Sessions for the GDI+ example how to draw the rounded rect:
https://www.codeproject.com/Articles/27228/A-class-for-creating-round-rectangles-in-GDI-with
#include <windows.h>
#include <objidl.h>
#include <gdiplus.h>
using namespace Gdiplus;
#pragma comment (lib,"Gdiplus.lib")
inline void GetRoundRectPath(GraphicsPath* pPath, Rect r, int dia)
{
// diameter can't exceed width or height
if (dia > r.Width) dia = r.Width;
if (dia > r.Height) dia = r.Height;
// define a corner
Rect Corner(r.X, r.Y, dia, dia);
// begin path
pPath->Reset();
// top left
pPath->AddArc(Corner, 180, 90);
// top right
Corner.X += (r.Width - dia - 1);
pPath->AddArc(Corner, 270, 90);
// bottom right
Corner.Y += (r.Height - dia - 1);
pPath->AddArc(Corner, 0, 90);
// bottom left
Corner.X -= (r.Width - dia - 1);
pPath->AddArc(Corner, 90, 90);
// end path
pPath->CloseFigure();
}
inline void GetChildRect(HWND hChild, LPRECT rc)
{
GetWindowRect(hChild,rc);
SIZE si = { rc->right - rc->left, rc->bottom - rc->top };
ScreenToClient(GetParent(hChild), (LPPOINT)rc);
rc->right = rc->left + si.cx;
rc->bottom = rc->top + si.cy;
}
inline void DrawRoundedBorder(HWND hWnd, COLORREF rgba = 0xFF0000FF, int radius = 5)
{
BYTE* c = (BYTE*)&rgba;
Pen pen(Color(c[0], c[1], c[2], c[3]));
if (pen.GetLastStatus() == GdiplusNotInitialized)
{
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
pen.SetColor(Color(c[0], c[1], c[2], c[3]));
}
pen.SetAlignment(PenAlignmentCenter);
SolidBrush brush(Color(255, 255, 255, 255));
RECT rc = { 0 };
GetChildRect(hWnd, &rc);
// the normal EX_CLIENTEDGE is 2 pixels thick.
// up to a radius of 5, this just works out.
// for a larger radius, the rectangle must be inflated
if (radius > 5)
{
int s = radius / 2 - 2;
InflateRect(&rc, s, s);
}
GraphicsPath path;
GetRoundRectPath(&path, Rect(rc.left, rc.top, rc.right - rc.left, rc.bottom - rc.top), radius * 2);
HWND hParent = GetParent(hWnd);
HDC hdc = GetDC(hParent);
Graphics graphics(hdc);
graphics.SetSmoothingMode(SmoothingModeAntiAlias);
graphics.FillPath(&brush, &path);
graphics.DrawPath(&pen, &path);
ReleaseDC(hParent, hdc);
}
static WNDPROC pfOldEditWndProc = NULL;
static LRESULT CALLBACK EditRounderBorderWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_NCCREATE:
{
DWORD style = GetWindowLong(hWnd, GWL_STYLE);
if (style & WS_BORDER)
{
// WS_EX_CLIENTEDGE style will make the border 2 pixels thick...
style = GetWindowLong(hWnd, GWL_EXSTYLE);
if (!(style & WS_EX_CLIENTEDGE))
{
style |= WS_EX_CLIENTEDGE;
SetWindowLong(hWnd, GWL_EXSTYLE, style);
}
}
// to draw on the parent DC, CLIPCHILDREN must be off
HWND hParent = GetParent(hWnd);
style = GetWindowLong(hParent, GWL_STYLE);
if (style & WS_CLIPCHILDREN)
{
style &= ~WS_CLIPCHILDREN;
SetWindowLong(hParent, GWL_STYLE, style);
}
}
break;
case WM_NCPAINT:
if (GetWindowLong(hWnd, GWL_EXSTYLE) & WS_EX_CLIENTEDGE)
{
DrawRoundedBorder(hWnd);
return 0;
}
}
return CallWindowProc(pfOldEditWndProc, hWnd, uMsg, wParam, lParam);
}
class CRoundedEditBorder
{
public:
CRoundedEditBorder()
{
Subclass();
}
~CRoundedEditBorder()
{
Unsubclass();
}
private:
void Subclass()
{
HWND hEdit = CreateWindow(L"EDIT", L"", 0, 0, 0, 200, 20, NULL, NULL, GetModuleHandle(NULL), NULL);
pfOldEditWndProc = (WNDPROC)GetClassLongPtr(hEdit, GCLP_WNDPROC);
SetClassLongPtr(hEdit, GCLP_WNDPROC, (LONG_PTR)EditRounderBorderWndProc);
DestroyWindow(hEdit);
}
void Unsubclass()
{
HWND hEdit = CreateWindow(L"EDIT", L"", 0, 0, 0, 200, 20, NULL, NULL, GetModuleHandle(NULL), NULL);
SetClassLongPtr(hEdit, GCLP_WNDPROC, (LONG_PTR)pfOldEditWndProc);
DestroyWindow(hEdit);
}
};
CRoundedEditBorder g_RoundedEditBorder;
LRESULT CALLBACK ParentWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_DESTROY: PostQuitMessage(0); return 0;
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
#define WNDCLASSNAME L"RoundedEditBorderTestClass"
int APIENTRY wWinMain(_In_ HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nCmdShow)
{
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
WNDCLASSEXW wcex = { sizeof(WNDCLASSEX), CS_HREDRAW|CS_VREDRAW,ParentWndProc,0,0,hInstance,NULL,NULL,CreateSolidBrush(GetSysColor(COLOR_BTNSHADOW)),NULL,WNDCLASSNAME,NULL };
RegisterClassExW(&wcex);
HWND hWnd = CreateWindowW(WNDCLASSNAME, L"Rounded Edit Border Test", WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);
CreateWindowEx(0, L"EDIT", L"no border", WS_CHILD | WS_VISIBLE, 10, 10, 200, 24, hWnd, NULL, GetModuleHandle(NULL), NULL);
CreateWindowEx(0, L"EDIT", L"no ex style", WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 50, 200, 24, hWnd, NULL, GetModuleHandle(NULL), NULL);
CreateWindowEx(WS_EX_CLIENTEDGE, L"EDIT", L"Ex_ClientEdge", WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 90, 200, 24, hWnd, NULL, GetModuleHandle(NULL), NULL);
ShowWindow(hWnd, nCmdShow);
MSG msg;
while (GetMessage(&msg, nullptr, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
GdiplusShutdown(gdiplusToken);
return (int)msg.wParam;
}
I'm trying to make Cairo work in a Win32 window. The idea is just to make it render flicker-free.
If I create a Cairo surface directly with the window's HDC, then the window will flicker on resizing. That's normal, and expected. The usual solution is to create a compatible device context and render to a bitmap, then blit that bitmap to the window HDC.
The problem is that the same drawing code that worked when using the window's HDC doesn't work on the double-buffer device context. I just get a black square rather than a gradient circle.
Here's a small, functional example. If you comment out the #define DOUBLE_BUFFER line, then it will draw the Cairo rendering directly to the window's HDC. Otherwise, it will draw to the created one.
#include <windows.h>
#include <stdlib.h>
#include <string.h>
#include <tchar.h>
#include <cairo.h>
#include <cairo-win32.h>
// Global variables
// The main window class name.
static TCHAR szWindowClass[] = _T("CairoTestApp");
// The string that appears in the application's title bar.
static TCHAR szTitle[] = _T("Cairo Test Application");
HINSTANCE hInst;
// Forward declarations of functions included in this code module:
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int main(int argc, const char *argv)
{
HINSTANCE hInstance = GetModuleHandle(NULL);
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
if (!RegisterClassEx(&wcex))
{
MessageBox(NULL, _T("Call to RegisterClassEx failed!"), szTitle, NULL);
return 1;
}
hInst = hInstance; // Store instance handle in our global variable
// The parameters to CreateWindow explained:
// szWindowClass: the name of the application
// szTitle: the text that appears in the title bar
// WS_OVERLAPPEDWINDOW: the type of window to create
// CW_USEDEFAULT, CW_USEDEFAULT: initial position (x, y)
// 500, 100: initial size (width, length)
// NULL: the parent of this window
// NULL: this application does not have a menu bar
// hInstance: the first parameter from WinMain
// NULL: not used in this application
HWND hWnd = CreateWindow(
szWindowClass,
szTitle,
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT,
256, 256,
NULL,
NULL,
hInstance,
NULL
);
if (!hWnd)
{
MessageBox(NULL, _T("Call to CreateWindow failed!"), szTitle, NULL);
return 1;
}
// The parameters to ShowWindow explained:
// hWnd: the value returned from CreateWindow
// nCmdShow: the fourth parameter from WinMain
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);
// Main message loop:
MSG msg;
while(true)
{
if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
if (msg.message == WM_QUIT)
{
break;
}
else
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
// DestroyWindow(hWnd);
UnregisterClass(szWindowClass, hInstance);
return 0;
}
void gradientExample( cairo_t* cr ) {
cairo_pattern_t *pat;
pat = cairo_pattern_create_linear (0.0, 0.0, 0.0, 256.0);
cairo_pattern_add_color_stop_rgba (pat, 1, 0, 0, 0, 1);
cairo_pattern_add_color_stop_rgba (pat, 0, 1, 1, 1, 1);
cairo_rectangle (cr, 0, 0, 256, 256);
cairo_set_source (cr, pat);
cairo_fill (cr);
cairo_pattern_destroy (pat);
pat = cairo_pattern_create_radial (115.2, 102.4, 25.6,
102.4, 102.4, 128.0);
cairo_pattern_add_color_stop_rgba (pat, 0, 1, 1, 1, 1);
cairo_pattern_add_color_stop_rgba (pat, 1, 0, 0, 0, 1);
cairo_set_source (cr, pat);
cairo_arc (cr, 128.0, 128.0, 76.8, 0, 2 * 3.14159);
cairo_fill (cr);
cairo_pattern_destroy (pat);
}
#define DOUBLE_BUFFER
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
TCHAR greeting[] = _T("Hello, World!");
switch (message)
{
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
{
HDC newDC = CreateCompatibleDC(hdc);
RECT theRect;
GetClientRect(hWnd, &theRect);
int width, height;
width = theRect.right - theRect.left;
height = theRect.bottom - theRect.top;
HBITMAP theBmp = CreateCompatibleBitmap(newDC, width, height);
HGDIOBJ oldBmp = SelectObject(newDC, theBmp);
//Test some text.
#ifdef DOUBLE_BUFFER
TextOut(newDC, 5, 5, greeting, _tcslen(greeting));
#else
TextOut(hdc, 5, 5, greeting, _tcslen(greeting));
#endif
{
#ifdef DOUBLE_BUFFER
cairo_surface_t *surface = cairo_win32_surface_create(newDC);
#else
cairo_surface_t *surface = cairo_win32_surface_create(hdc);
#endif
cairo_t *cr = cairo_create(surface);
// Draw on the cairo context.
cairo_set_source_rgb(cr, 1, 1, 1);
cairo_paint(cr);
gradientExample( cr );
cairo_surface_finish(surface);
// Cleanup.
cairo_destroy(cr);
cairo_surface_destroy(surface);
}
#ifdef DOUBLE_BUFFER
BitBlt(hdc, 0, 0, width, height, newDC, theRect.left, theRect.top, SRCCOPY);
#endif
SelectObject(newDC, oldBmp);
DeleteDC(newDC);
}
EndPaint(hWnd, &ps);
break;
case WM_ERASEBKGND:
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
case WM_KEYDOWN: // Is A Key Being Held Down?
{
if(wParam == VK_ESCAPE)
{
PostMessage(hWnd, WM_CLOSE, 0, 0);
}
}
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
break;
}
return 0;
}
Try calling CreateCompatibleBitmap with the original device context (hdc) as parameter instead. Otherwise I believe you'll get one based on the default monochrome dummy bitmap of the supposedly-compatible DC you just created.