another UI attempt, I guess.

sorry.

1 files changed, 247 insertions, 0 deletions

diff --git a/src/libui_sdl/libui/windows/areascroll.cpp b/src/libui_sdl/libui/windows/areascroll.cpp
new file mode 100644
index 0000000..f18d0ad
--- /dev/null
+++ b/src/libui_sdl/libui/windows/areascroll.cpp
@@ -0,0 +1,247 @@
+// 8 september 2015
+#include "uipriv_windows.hpp"
+#include "area.hpp"
+
+// TODO
+// - move from pixels to points somehow
+// 	- add a function to offset points and rects by scrolling amounts; call it from doPaint() in areadraw.c
+// - recalculate scrolling after:
+// 	- creation?
+// 	- resize?
+// 	- recreating the render target? (after moving to points)
+// - error if these are called without scrollbars?
+
+struct scrollParams {
+	int *pos;
+	int pagesize;
+	int length;
+	int *wheelCarry;
+	UINT wheelSPIAction;
+};
+
+static void scrollto(uiArea *a, int which, struct scrollParams *p, int pos)
+{
+	SCROLLINFO si;
+
+	// note that the pos < 0 check is /after/ the p->length - p->pagesize check
+	// it used to be /before/; this was actually a bug in Raymond Chen's original algorithm: if there are fewer than a page's worth of items, p->length - p->pagesize will be negative and our content draw at the bottom of the window
+	// this SHOULD have the same effect with that bug fixed and no others introduced... (thanks to devin on irc.badnik.net for confirming this logic)
+	if (pos > p->length - p->pagesize)
+		pos = p->length - p->pagesize;
+	if (pos < 0)
+		pos = 0;
+
+	// Direct2D doesn't have a method for scrolling the existing contents of a render target.
+	// We'll have to just invalidate everything and hope for the best.
+	invalidateRect(a->hwnd, NULL, FALSE);
+
+	*(p->pos) = pos;
+
+	// now commit our new scrollbar setup...
+	ZeroMemory(&si, sizeof (SCROLLINFO));
+	si.cbSize = sizeof (SCROLLINFO);
+	si.fMask = SIF_PAGE | SIF_POS | SIF_RANGE;
+	si.nPage = p->pagesize;
+	si.nMin = 0;
+	si.nMax = p->length - 1;		// endpoint inclusive
+	si.nPos = *(p->pos);
+	SetScrollInfo(a->hwnd, which, &si, TRUE);
+}
+
+static void scrollby(uiArea *a, int which, struct scrollParams *p, int delta)
+{
+	scrollto(a, which, p, *(p->pos) + delta);
+}
+
+static void scroll(uiArea *a, int which, struct scrollParams *p, WPARAM wParam, LPARAM lParam)
+{
+	int pos;
+	SCROLLINFO si;
+
+	pos = *(p->pos);
+	switch (LOWORD(wParam)) {
+	case SB_LEFT:			// also SB_TOP
+		pos = 0;
+		break;
+	case SB_RIGHT:		// also SB_BOTTOM
+		pos = p->length - p->pagesize;
+		break;
+	case SB_LINELEFT:		// also SB_LINEUP
+		pos--;
+		break;
+	case SB_LINERIGHT:		// also SB_LINEDOWN
+		pos++;
+		break;
+	case SB_PAGELEFT:		// also SB_PAGEUP
+		pos -= p->pagesize;
+		break;
+	case SB_PAGERIGHT:	// also SB_PAGEDOWN
+		pos += p->pagesize;
+		break;
+	case SB_THUMBPOSITION:
+		ZeroMemory(&si, sizeof (SCROLLINFO));
+		si.cbSize = sizeof (SCROLLINFO);
+		si.fMask = SIF_POS;
+		if (GetScrollInfo(a->hwnd, which, &si) == 0)
+			logLastError(L"error getting thumb position for area");
+		pos = si.nPos;
+		break;
+	case SB_THUMBTRACK:
+		ZeroMemory(&si, sizeof (SCROLLINFO));
+		si.cbSize = sizeof (SCROLLINFO);
+		si.fMask = SIF_TRACKPOS;
+		if (GetScrollInfo(a->hwnd, which, &si) == 0)
+			logLastError(L"error getting thumb track position for area");
+		pos = si.nTrackPos;
+		break;
+	}
+	scrollto(a, which, p, pos);
+}
+
+static void wheelscroll(uiArea *a, int which, struct scrollParams *p, WPARAM wParam, LPARAM lParam)
+{
+	int delta;
+	int lines;
+	UINT scrollAmount;
+
+	delta = GET_WHEEL_DELTA_WPARAM(wParam);
+	if (SystemParametersInfoW(p->wheelSPIAction, 0, &scrollAmount, 0) == 0)
+		// TODO use scrollAmount == 3 (for both v and h) instead?
+		logLastError(L"error getting area wheel scroll amount");
+	if (scrollAmount == WHEEL_PAGESCROLL)
+		scrollAmount = p->pagesize;
+	if (scrollAmount == 0)		// no mouse wheel scrolling (or t->pagesize == 0)
+		return;
+	// the rest of this is basically http://blogs.msdn.com/b/oldnewthing/archive/2003/08/07/54615.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2003/08/11/54624.aspx
+	// see those pages for information on subtleties
+	delta += *(p->wheelCarry);
+	lines = delta * ((int) scrollAmount) / WHEEL_DELTA;
+	*(p->wheelCarry) = delta - lines * WHEEL_DELTA / ((int) scrollAmount);
+	scrollby(a, which, p, -lines);
+}
+
+static void hscrollParams(uiArea *a, struct scrollParams *p)
+{
+	RECT r;
+
+	ZeroMemory(p, sizeof (struct scrollParams));
+	p->pos = &(a->hscrollpos);
+	// TODO get rid of these and replace with points
+	uiWindowsEnsureGetClientRect(a->hwnd, &r);
+	p->pagesize = r.right - r.left;
+	p->length = a->scrollWidth;
+	p->wheelCarry = &(a->hwheelCarry);
+	p->wheelSPIAction = SPI_GETWHEELSCROLLCHARS;
+}
+
+static void hscrollto(uiArea *a, int pos)
+{
+	struct scrollParams p;
+
+	hscrollParams(a, &p);
+	scrollto(a, SB_HORZ, &p, pos);
+}
+
+static void hscrollby(uiArea *a, int delta)
+{
+	struct scrollParams p;
+
+	hscrollParams(a, &p);
+	scrollby(a, SB_HORZ, &p, delta);
+}
+
+static void hscroll(uiArea *a, WPARAM wParam, LPARAM lParam)
+{
+	struct scrollParams p;
+
+	hscrollParams(a, &p);
+	scroll(a, SB_HORZ, &p, wParam, lParam);
+}
+
+static void hwheelscroll(uiArea *a, WPARAM wParam, LPARAM lParam)
+{
+	struct scrollParams p;
+
+	hscrollParams(a, &p);
+	wheelscroll(a, SB_HORZ, &p, wParam, lParam);
+}
+
+static void vscrollParams(uiArea *a, struct scrollParams *p)
+{
+	RECT r;
+
+	ZeroMemory(p, sizeof (struct scrollParams));
+	p->pos = &(a->vscrollpos);
+	uiWindowsEnsureGetClientRect(a->hwnd, &r);
+	p->pagesize = r.bottom - r.top;
+	p->length = a->scrollHeight;
+	p->wheelCarry = &(a->vwheelCarry);
+	p->wheelSPIAction = SPI_GETWHEELSCROLLLINES;
+}
+
+static void vscrollto(uiArea *a, int pos)
+{
+	struct scrollParams p;
+
+	vscrollParams(a, &p);
+	scrollto(a, SB_VERT, &p, pos);
+}
+
+static void vscrollby(uiArea *a, int delta)
+{
+	struct scrollParams p;
+
+	vscrollParams(a, &p);
+	scrollby(a, SB_VERT, &p, delta);
+}
+
+static void vscroll(uiArea *a, WPARAM wParam, LPARAM lParam)
+{
+	struct scrollParams p;
+
+	vscrollParams(a, &p);
+	scroll(a, SB_VERT, &p, wParam, lParam);
+}
+
+static void vwheelscroll(uiArea *a, WPARAM wParam, LPARAM lParam)
+{
+	struct scrollParams p;
+
+	vscrollParams(a, &p);
+	wheelscroll(a, SB_VERT, &p, wParam, lParam);
+}
+
+BOOL areaDoScroll(uiArea *a, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT *lResult)
+{
+	switch (uMsg) {
+	case WM_HSCROLL:
+		hscroll(a, wParam, lParam);
+		*lResult = 0;
+		return TRUE;
+	case WM_MOUSEHWHEEL:
+		hwheelscroll(a, wParam, lParam);
+		*lResult = 0;
+		return TRUE;
+	case WM_VSCROLL:
+		vscroll(a, wParam, lParam);
+		*lResult = 0;
+		return TRUE;
+	case WM_MOUSEWHEEL:
+		vwheelscroll(a, wParam, lParam);
+		*lResult = 0;
+		return TRUE;
+	}
+	return FALSE;
+}
+
+void areaScrollOnResize(uiArea *a, RECT *client)
+{
+	areaUpdateScroll(a);
+}
+
+void areaUpdateScroll(uiArea *a)
+{
+	// use a no-op scroll to simulate scrolling
+	hscrollby(a, 0);
+	vscrollby(a, 0);
+}