My environment: (WinXP, MinGW (gcc-4.6.2), Cairo-1.12.2, Pixman-0.26.0) Test program follows: #include <windows.h> #include <math.h> #include <cairo.h> //#if CAIRO_HAS_XLIB_SURFACE // #include <X11/Xlib.h> // #include <gtk/gtk.h> // #include <gdk/gdk.h> //#endif #if CAIRO_HAS_SVG_SURFACE #include <cairo-svg.h> #endif #if CAIRO_HAS_PDF_SURFACE #include <cairo-pdf.h> #endif #if CAIRO_HAS_PS_SURFACE #include <cairo-ps.h> #endif #if CAIRO_HAS_XCB_SURFACE #include <cairo-xcb.h> #endif #if CAIRO_HAS_XLIB_SURFACE #include <cairo-xlib.h> #endif #if CAIRO_HAS_WIN32_SURFACE #include <cairo-win32.h> #endif #if CAIRO_HAS_BEOS_SURFACE #include <cairo-beos.h> #endif #if CAIRO_HAS_DIRECTFB_SURFACE #include <cairo-directfb.h> #endif #if CAIRO_HAS_OS2_SURFACE #include <cairo-os2.h> #endif #if CAIRO_HAS_GLITZ_SURFACE #include <cairo-glitz.h> #endif #if CAIRO_HAS_QUARTZ_SURFACE #include <cairo-quartz.h> #endif #if CAIRO_HAS_ATSUI_FONT #include <cairo-atsui.h> #endif #if CAIRO_HAS_FT_FONT #include <cairo-ft.h> #endif /* Declare Windows procedure */ LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM); /* Make the class name into a global variable */ const wchar_t* szClassName = L"CairoTest"; 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 */ L"CairoTest", /* 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; } static void snap_point (cairo_t *cr, double *x, double *y, bool odd_integer_line_width = true) { cairo_user_to_device (cr, x, y); if (odd_integer_line_width) { // round to nearest half integer *x = round (*x) + .5; *y = round (*y) + .5; } else { // round to nearest integer *x = round (*x); *y = round (*y); } cairo_device_to_user (cr, x, y); } static double snapx(cairo_t* cr, double ax) { double x = ax; double y = 0; snap_point(cr, &x, &y); return x; } static double snapy(cairo_t* cr, double ay) { double x = 0; double y = ay; snap_point(cr, &x, &y); return y; } static void draw_grid_lines(cairo_t* cr, int maxx, int maxy, int step, double linewidth) { for (int x = 0; x < maxx; x += step) { cairo_move_to (cr, snapx(cr,x), snapy(cr,0)); cairo_line_to (cr, snapx(cr,x), snapy(cr,maxy)); cairo_close_path(cr); } for (int y = 0; y < maxy; y += step) { cairo_move_to (cr, snapx(cr,0), snapy(cr,y)); cairo_line_to (cr, snapx(cr,maxx), snapy(cr,y)); cairo_close_path(cr); } //cairo_set_source_rgb(cr, 0.84, 0.84, 0.84); //paper color: Dim Grey cairo_set_source_rgb(cr, 0.64, 0.64, 0.64); //? cairo_save(cr); { cairo_identity_matrix (cr); cairo_set_line_width (cr, linewidth); cairo_stroke (cr); } cairo_restore(cr); } static void draw_grid(cairo_t* cr, int pw, int ph, int zoom) { cairo_save(cr); { // line positions in mm if (0 < zoom && zoom <= 100) { draw_grid_lines(cr, pw, ph, 1000, .2); } else if (100 < zoom && zoom <= 250) { draw_grid_lines(cr, pw, ph, 1000, .2); } else if (250 < zoom) { draw_grid_lines(cr, pw, ph, 500, .2); draw_grid_lines(cr, pw, ph, 1000, .4); } } cairo_restore(cr); } static void draw_paper(cairo_t* cr, double sf, int pw, int ph) { double shadow = 3.0 / sf; cairo_save(cr); { cairo_rectangle (cr, shadow, shadow, pw, ph); cairo_set_source_rgb(cr, 0.0, 0.0, 0.0); cairo_fill(cr); cairo_rectangle (cr, 0, 0, pw, ph); cairo_set_source_rgb(cr, 0.84, 0.84, 0.84); //Dim Grey cairo_fill(cr); } cairo_restore(cr); } PAINTSTRUCT ps; HDC hdc; void dopainting(HDC hdc) { cairo_t *cr = cairo_create(cairo_win32_surface_create( hdc )); // dark gray background cairo_set_source_rgb(cr, 0.5, 0.5, 0.5); cairo_paint(cr); draw_paper(cr, 1.0, 500, 500); draw_grid(cr, 500, 500, 100); cairo_destroy(cr); } /* This function is called by the Windows function DispatchMessage() */ LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) /* handle the messages */ { case WM_DESTROY: PostQuitMessage (0); /* send a WM_QUIT to the message queue */ break; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); dopainting(hdc); EndPaint(hwnd, &ps); ValidateRect(hwnd, NULL); break; default: /* for messages that we don't deal with */ return DefWindowProc (hwnd, message, wParam, lParam); } return 0; }
Created attachment 85688 [details] [review] quick hack This is a quick hack that apparently fixes the issue in this example and in the snippet code described in the thread related to http://lists.cairographics.org/archives/cairo/2013-September/024626.html Basically it enlarges the fallback surface created of the amount necessary not to write past the end of the DIB. It assumes that Clip applied to an HDC are clamped to (0,0,width,height) of the HDC. HTH
The patch (attachment 85688 [details] [review]) appears to be fixing my problems with RGBA windows ( https://bugzilla.gnome.org/show_bug.cgi?id=727316 and http://lists.cairographics.org/archives/cairo/2014-April/025147.html ).
The patch (attachment 85688 [details] [review]) seems to work for me, too. We have incorporated the patch into our build of Cairo to be distributed with the next release of Racket.
Thanks, patch applied: cca8b19..91f128b master -> master
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