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andlabs-ui/area_windows.c

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// 24 march 2014
#include "winapi_windows.h"
#include "_cgo_export.h"
static void getScrollPos(HWND hwnd, int *xpos, int *ypos)
{
SCROLLINFO si;
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_POS | SIF_TRACKPOS;
if (GetScrollInfo(hwnd, SB_HORZ, &si) == 0)
xpanic("error getting horizontal scroll position for Area", GetLastError());
*xpos = si.nPos;
// MSDN example code reinitializes this each time, so we'll do it too just to be safe
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_POS | SIF_TRACKPOS;
if (GetScrollInfo(hwnd, SB_VERT, &si) == 0)
xpanic("error getting vertical scroll position for Area", GetLastError());
*ypos = si.nPos;
}
#define areaBackgroundBrush ((HBRUSH) (COLOR_BTNFACE + 1))
static void paintArea(HWND hwnd, void *data)
{
RECT xrect;
PAINTSTRUCT ps;
HDC hdc;
HDC rdc;
HBITMAP rbitmap, prevrbitmap;
RECT rrect;
BITMAPINFO bi;
VOID *ppvBits;
HBITMAP ibitmap;
HDC idc;
HBITMAP previbitmap;
BLENDFUNCTION blendfunc;
void *i;
intptr_t dx, dy;
int hscroll, vscroll;
// FALSE here indicates don't send WM_ERASEBKGND
if (GetUpdateRect(hwnd, &xrect, FALSE) == 0)
return; // no update rect; do nothing
getScrollPos(hwnd, &hscroll, &vscroll);
hdc = BeginPaint(hwnd, &ps);
if (hdc == NULL)
xpanic("error beginning Area repaint", GetLastError());
// very big thanks to Ninjifox for suggesting this technique and helping me go through it
// first let's create the destination image, which we fill with the windows background color
// this is how we fake drawing the background; see also http://msdn.microsoft.com/en-us/library/ms969905.aspx
rdc = CreateCompatibleDC(hdc);
if (rdc == NULL)
xpanic("error creating off-screen rendering DC", GetLastError());
// the bitmap has to be compatible with the window
// if we create a bitmap compatible with the DC we just created, it'll be monochrome
// thanks to David Heffernan in http://stackoverflow.com/questions/23033636/winapi-gdi-fillrectcolor-btnface-fills-with-strange-grid-like-brush-on-window
rbitmap = CreateCompatibleBitmap(hdc, xrect.right - xrect.left, xrect.bottom - xrect.top);
if (rbitmap == NULL)
xpanic("error creating off-screen rendering bitmap", GetLastError());
prevrbitmap = (HBITMAP) SelectObject(rdc, rbitmap);
if (prevrbitmap == NULL)
xpanic("error connecting off-screen rendering bitmap to off-screen rendering DC", GetLastError());
rrect.left = 0;
rrect.right = xrect.right - xrect.left;
rrect.top = 0;
rrect.bottom = xrect.bottom - xrect.top;
if (FillRect(rdc, &rrect, areaBackgroundBrush) == 0)
xpanic("error filling off-screen rendering bitmap with the system background color", GetLastError());
i = doPaint(&xrect, hscroll, vscroll, data, &dx, &dy);
if (i == NULL) // cliprect empty
goto nobitmap; // we need to blit the background no matter what
// now we need to shove realbits into a bitmap
// technically bitmaps don't know about alpha; they just ignore the alpha byte
// AlphaBlend(), however, sees it - see http://msdn.microsoft.com/en-us/library/windows/desktop/dd183352%28v=vs.85%29.aspx
ZeroMemory(&bi, sizeof (BITMAPINFO));
bi.bmiHeader.biSize = sizeof (BITMAPINFOHEADER);
bi.bmiHeader.biWidth = (LONG) dx;
bi.bmiHeader.biHeight = -((LONG) dy); // negative height to force top-down drawing
bi.bmiHeader.biPlanes = 1;
bi.bmiHeader.biBitCount = 32;
bi.bmiHeader.biCompression = BI_RGB;
bi.bmiHeader.biSizeImage = (DWORD) (dx * dy * 4);
// this is all we need, but because this confused me at first, I will say the two pixels-per-meter fields are unused (see http://blogs.msdn.com/b/oldnewthing/archive/2013/05/15/10418646.aspx and page 581 of Charles Petzold's Programming Windows, Fifth Edition)
// now for the trouble: CreateDIBSection() allocates the memory for us...
ibitmap = CreateDIBSection(NULL, // Ninjifox does this, so do some wine tests (http://source.winehq.org/source/dlls/gdi32/tests/bitmap.c#L725, thanks vpovirk in irc.freenode.net/#winehackers) and even Raymond Chen (http://blogs.msdn.com/b/oldnewthing/archive/2006/11/16/1086835.aspx), so.
&bi, DIB_RGB_COLORS, &ppvBits, 0, 0);
if (ibitmap == NULL)
xpanic("error creating HBITMAP for image returned by AreaHandler.Paint()", GetLastError());
// now we have to do TWO MORE things before we can finally do alpha blending
// first, we need to load the bitmap memory, because Windows makes it for us
// the pixels are arranged in RGBA order, but GDI requires BGRA
// this turns out to be just ARGB in little endian; let's convert into this memory
dotoARGB(i, (void *) ppvBits, FALSE); // FALSE = not NRGBA
// the second thing is... make a device context for the bitmap :|
// Ninjifox just makes another compatible DC; we'll do the same
idc = CreateCompatibleDC(hdc);
if (idc == NULL)
xpanic("error creating HDC for image returned by AreaHandler.Paint()", GetLastError());
previbitmap = (HBITMAP) SelectObject(idc, ibitmap);
if (previbitmap == NULL)
xpanic("error connecting HBITMAP for image returned by AreaHandler.Paint() to its HDC", GetLastError());
// AND FINALLY WE CAN DO THE ALPHA BLENDING!!!!!!111
blendfunc.BlendOp = AC_SRC_OVER;
blendfunc.BlendFlags = 0;
blendfunc.SourceConstantAlpha = 255; // only use per-pixel alphas
blendfunc.AlphaFormat = AC_SRC_ALPHA; // premultiplied
if (AlphaBlend(rdc, 0, 0, (int) dx, (int) dy, // destination
idc, 0, 0, (int) dx, (int)dy, // source
blendfunc) == FALSE)
xpanic("error alpha-blending image returned by AreaHandler.Paint() onto background", GetLastError());
// clean up after idc/ibitmap here because of the goto nobitmap
if (SelectObject(idc, previbitmap) != ibitmap)
xpanic("error reverting HDC for image returned by AreaHandler.Paint() to original HBITMAP", GetLastError());
if (DeleteObject(ibitmap) == 0)
xpanic("error deleting HBITMAP for image returned by AreaHandler.Paint()", GetLastError());
if (DeleteDC(idc) == 0)
xpanic("error deleting HDC for image returned by AreaHandler.Paint()", GetLastError());
nobitmap:
// and finally we can just blit that into the window
if (BitBlt(hdc, xrect.left, xrect.top, xrect.right - xrect.left, xrect.bottom - xrect.top,
rdc, 0, 0, // from the rdc's origin
SRCCOPY) == 0)
xpanic("error blitting Area image to Area", GetLastError());
// now to clean up
if (SelectObject(rdc, prevrbitmap) != rbitmap)
xpanic("error reverting HDC for off-screen rendering to original HBITMAP", GetLastError());
if (DeleteObject(rbitmap) == 0)
xpanic("error deleting HBITMAP for off-screen rendering", GetLastError());
if (DeleteDC(rdc) == 0)
xpanic("error deleting HDC for off-screen rendering", GetLastError());
EndPaint(hwnd, &ps);
}
static SIZE getAreaControlSize(HWND hwnd)
{
RECT rect;
SIZE size;
if (GetClientRect(hwnd, &rect) == 0)
xpanic("error getting size of actual Area control", GetLastError());
size.cx = (LONG) (rect.right - rect.left);
size.cy = (LONG) (rect.bottom - rect.top);
return size;
}
static void scrollArea(HWND hwnd, void *data, WPARAM wParam, int which)
{
SCROLLINFO si;
SIZE size;
LONG cwid, cht;
LONG pagesize, maxsize;
LONG newpos;
LONG delta;
LONG dx, dy;
size = getAreaControlSize(hwnd);
cwid = size.cx;
cht = size.cy;
if (which == SB_HORZ) {
pagesize = cwid;
maxsize = areaWidthLONG(data);
} else if (which == SB_VERT) {
pagesize = cht;
maxsize = areaHeightLONG(data);
} else
xpanic("invalid which sent to scrollArea()", 0);
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_POS | SIF_TRACKPOS;
if (GetScrollInfo(hwnd, which, &si) == 0)
xpanic("error getting current scroll position for scrolling", GetLastError());
newpos = (LONG) si.nPos;
switch (LOWORD(wParam)) {
case SB_LEFT: // also SB_TOP; C won't let me have both (C89 §6.6.4.2; C99 §6.8.4.2)
newpos = 0;
break;
case SB_RIGHT: // also SB_BOTTOM
// see comment in adjustAreaScrollbars() below
newpos = maxsize - pagesize;
break;
case SB_LINELEFT: // also SB_LINEUP
newpos--;
break;
case SB_LINERIGHT: // also SB_LINEDOWN
newpos++;
break;
case SB_PAGELEFT: // also SB_PAGEUP
newpos -= pagesize;
break;
case SB_PAGERIGHT: // also SB_PAGEDOWN
newpos += pagesize;
break;
case SB_THUMBPOSITION:
// raymond chen says to just set the newpos to the SCROLLINFO nPos for this message; see http://blogs.msdn.com/b/oldnewthing/archive/2003/07/31/54601.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2003/08/05/54602.aspx
// do nothing here; newpos already has nPos
break;
case SB_THUMBTRACK:
newpos = (LONG) si.nTrackPos;
}
// otherwise just keep the current position (that's what MSDN example code says, anyway)
// make sure we're not out of range
if (newpos < 0)
newpos = 0;
if (newpos > (maxsize - pagesize))
newpos = maxsize - pagesize;
// this would be where we would put a check to not scroll if the scroll position changed, but see the note about SB_THUMBPOSITION above: Raymond Chen's code always does the scrolling anyway in this case
delta = -(newpos - si.nPos); // negative because ScrollWindowEx() scrolls in the opposite direction
dx = delta;
dy = 0;
if (which == SB_VERT) {
dx = 0;
dy = delta;
}
// this automatically scrolls the edit control, if any
if (ScrollWindowEx(hwnd,
(int) dx, (int) dy,
// these four change what is scrolled and record info about the scroll; we're scrolling the whole client area and don't care about the returned information here
NULL, NULL, NULL, NULL,
// mark the remaining rect as needing redraw and erase...
SW_INVALIDATE | SW_ERASE) == ERROR)
xpanic("error scrolling Area", GetLastError());
// ...but don't redraw the window yet; we need to apply our scroll changes
// we actually have to commit the change back to the scrollbar; otherwise the scroll position will merely reset itself
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_POS;
si.nPos = (int) newpos;
// this is not expressly documented as returning an error so IDK what the error code is so assume there is none
SetScrollInfo(hwnd, which, &si, TRUE); // redraw scrollbar
// NOW redraw it
if (UpdateWindow(hwnd) == 0)
xpanic("error updating Area after scrolling", GetLastError());
if ((HWND) GetWindowLongPtrW(hwnd, 0) != NULL)
if (UpdateWindow((HWND) GetWindowLongPtrW(hwnd, 0)) == 0)
xpanic("error updating Area TextField after scrolling", GetLastError());
}
static void adjustAreaScrollbars(HWND hwnd, void *data)
{
SCROLLINFO si;
SIZE size;
LONG cwid, cht;
size = getAreaControlSize(hwnd);
cwid = size.cx;
cht = size.cy;
// the trick is we want a page to be the width/height of the visible area
// so the scroll range would go from [0..image_dimension - control_dimension]
// but judging from the sample code on MSDN, we don't need to do this; the scrollbar will do it for us
// we DO need to handle it when scrolling, though, since the thumb can only go up to this upper limit
// have to do horizontal and vertical separately
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = (int) (areaWidthLONG(data) - 1); // the max point is inclusive, so we have to pass in the last valid value, not the first invalid one (see http://blogs.msdn.com/b/oldnewthing/archive/2003/07/31/54601.aspx); if we don't, we get weird things like the scrollbar sometimes showing one extra scroll position at the end that you can never scroll to
si.nPage = (UINT) cwid;
SetScrollInfo(hwnd, SB_HORZ, &si, TRUE); // redraw the scroll bar
// MSDN sample code does this a second time; let's do it too to be safe
ZeroMemory(&si, sizeof (SCROLLINFO));
si.cbSize = sizeof (SCROLLINFO);
si.fMask = SIF_RANGE | SIF_PAGE;
si.nMin = 0;
si.nMax = (int) (areaHeightLONG(data) - 1);
si.nPage = (UINT) cht;
SetScrollInfo(hwnd, SB_VERT, &si, TRUE);
}
void repaintArea(HWND hwnd, RECT *r)
{
// NULL - the whole area; TRUE - have windows erase if possible
if (InvalidateRect(hwnd, r, TRUE) == 0)
xpanic("error flagging Area as needing repainting after event", GetLastError());
if (UpdateWindow(hwnd) == 0)
xpanic("error repainting Area after event", GetLastError());
}
void areaMouseEvent(HWND hwnd, void *data, DWORD button, BOOL up, uintptr_t heldButtons, LPARAM lParam)
{
int xpos, ypos;
// mouse coordinates are relative to control; make them relative to Area
getScrollPos(hwnd, &xpos, &ypos);
xpos += GET_X_LPARAM(lParam);
ypos += GET_Y_LPARAM(lParam);
finishAreaMouseEvent(data, button, up, heldButtons, xpos, ypos);
}
static LRESULT CALLBACK areaWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
void *data;
DWORD which;
uintptr_t heldButtons = (uintptr_t) wParam;
LRESULT lResult;
data = getWindowData(hwnd, uMsg, wParam, lParam, &lResult);
if (data == NULL)
return lResult;
switch (uMsg) {
case WM_PAINT:
paintArea(hwnd, data);
return 0;
case WM_ERASEBKGND:
// don't draw a background; we'll do so when painting
// this is to make things flicker-free; see http://msdn.microsoft.com/en-us/library/ms969905.aspx
return 1;
case WM_HSCROLL:
scrollArea(hwnd, data, wParam, SB_HORZ);
return 0;
case WM_VSCROLL:
scrollArea(hwnd, data, wParam, SB_VERT);
return 0;
case WM_SIZE:
adjustAreaScrollbars(hwnd, data);
return 0;
case WM_ACTIVATE:
// don't keep the double-click timer running if the user switched programs in between clicks
areaResetClickCounter(data);
return 0;
case WM_MOUSEMOVE:
areaMouseEvent(hwnd, data, 0, FALSE, heldButtons, lParam);
return 0;
case WM_LBUTTONDOWN:
SetFocus(hwnd);
areaMouseEvent(hwnd, data, 1, FALSE, heldButtons, lParam);
return 0;
case WM_LBUTTONUP:
areaMouseEvent(hwnd, data, 1, TRUE, heldButtons, lParam);
return 0;
case WM_MBUTTONDOWN:
SetFocus(hwnd);
areaMouseEvent(hwnd, data, 2, FALSE, heldButtons, lParam);
return 0;
case WM_MBUTTONUP:
areaMouseEvent(hwnd, data, 2, TRUE, heldButtons, lParam);
return 0;
case WM_RBUTTONDOWN:
SetFocus(hwnd);
areaMouseEvent(hwnd, data, 3, FALSE, heldButtons, lParam);
return 0;
case WM_RBUTTONUP:
areaMouseEvent(hwnd, data, 3, TRUE, heldButtons, lParam);
return 0;
case WM_XBUTTONDOWN:
SetFocus(hwnd);
// values start at 1; we want them to start at 4
which = (DWORD) GET_XBUTTON_WPARAM(wParam) + 3;
heldButtons = (uintptr_t) GET_KEYSTATE_WPARAM(wParam);
areaMouseEvent(hwnd, data, which, FALSE, heldButtons, lParam);
return TRUE; // XBUTTON messages are different!
case WM_XBUTTONUP:
which = (DWORD) GET_XBUTTON_WPARAM(wParam) + 3;
heldButtons = (uintptr_t) GET_KEYSTATE_WPARAM(wParam);
areaMouseEvent(hwnd, data, which, TRUE, heldButtons, lParam);
return TRUE;
case msgAreaKeyDown:
return (LRESULT) areaKeyEvent(data, FALSE, wParam, lParam);
case msgAreaKeyUp:
return (LRESULT) areaKeyEvent(data, TRUE, wParam, lParam);
case msgAreaSizeChanged:
adjustAreaScrollbars(hwnd, data);
repaintArea(hwnd, NULL); // this calls for an update
return 0;
case msgAreaGetScroll:
getScrollPos(hwnd, (int *) wParam, (int *) lParam);
return 0;
case msgAreaRepaint:
repaintArea(hwnd, (RECT *) lParam);
return 0;
case msgAreaRepaintAll:
repaintArea(hwnd, NULL);
return 0;
default:
return DefWindowProcW(hwnd, uMsg, wParam, lParam);
}
xmissedmsg("Area", "areaWndProc()", uMsg);
return 0; // unreached
}
DWORD makeAreaWindowClass(char **errmsg)
{
WNDCLASSW wc;
ZeroMemory(&wc, sizeof (WNDCLASSW));
wc.style = CS_HREDRAW | CS_VREDRAW; // no CS_DBLCLKS because do that manually
wc.lpszClassName = areaWindowClass;
wc.lpfnWndProc = areaWndProc;
wc.hInstance = hInstance;
wc.hIcon = hDefaultIcon;
wc.hCursor = hArrowCursor,
wc.hbrBackground = NULL; // no brush; we handle WM_ERASEBKGND
wc.cbWndExtra = 3 * sizeof (LONG_PTR); // text field handle, text field current x, text field current y
if (RegisterClassW(&wc) == 0) {
*errmsg = "error registering Area window class";
return GetLastError();
}
return 0;
}
HWND newArea(void *data)
{
HWND hwnd;
hwnd = CreateWindowExW(
0,
areaWindowClass, L"",
WS_HSCROLL | WS_VSCROLL | WS_CHILD | WS_VISIBLE | WS_TABSTOP,
CW_USEDEFAULT, CW_USEDEFAULT,
100, 100,
msgwin, NULL, hInstance, data);
if (hwnd == NULL)
xpanic("container creation failed", GetLastError());
return hwnd;
}
static LRESULT CALLBACK areaTextFieldSubProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR id, DWORD_PTR data)
{
switch (uMsg) {
case WM_KILLFOCUS:
ShowWindow(hwnd, SW_HIDE);
areaTextFieldDone((void *) data);
return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
case WM_NCDESTROY:
if ((*fv_RemoveWindowSubclass)(hwnd, areaTextFieldSubProc, id) == FALSE)
xpanic("error removing Area TextField subclass (which was for handling WM_KILLFOCUS)", GetLastError());
return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
default:
return (*fv_DefSubclassProc)(hwnd, uMsg, wParam, lParam);
}
xmissedmsg("Area TextField", "areaTextFieldSubProc()", uMsg);
return 0; // unreached
}
HWND newAreaTextField(HWND area, void *goarea)
{
HWND tf;
tf = CreateWindowExW(textfieldExtStyle,
L"edit", L"",
textfieldStyle | WS_CHILD,
0, 0, 0, 0,
area, NULL, hInstance, NULL);
if (tf == NULL)
xpanic("error making Area TextField", GetLastError());
if ((*fv_SetWindowSubclass)(tf, areaTextFieldSubProc, 0, (DWORD_PTR) goarea) == FALSE)
xpanic("error subclassing Area TextField to give it its own WM_KILLFOCUS handler", GetLastError());
return tf;
}
void areaOpenTextField(HWND area, HWND textfield, int x, int y, int width, int height)
{
int sx, sy;
int baseX, baseY;
LONG unused;
getScrollPos(area, &sx, &sy);
x += sx;
y += sy;
calculateBaseUnits(textfield, &baseX, &baseY, &unused);
width = MulDiv(width, baseX, 4);
height = MulDiv(height, baseY, 8);
if (MoveWindow(textfield, x, y, width, height, TRUE) == 0)
xpanic("error moving Area TextField in Area.OpenTextFieldAt()", GetLastError());
ShowWindow(textfield, SW_SHOW);
if (SetFocus(textfield) == NULL)
xpanic("error giving Area TextField focus", GetLastError());
}
void areaMarkTextFieldDone(HWND area)
{
SetWindowLongPtrW(area, 0, (LONG_PTR) NULL);
}
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