Finished the Windows draw.c.

gtkarea/ui.h

@@ -56,7 +56,6 @@ enum uiDrawLineJoin {
 #define uiDrawDefaultMiterLimit 10.0
 
 // TODOs
-// - windows: SetPolyFillMode
 // - os x: FillPath/EOFillPath functions
 enum uiDrawFillMode {
 	uiDrawFillModeWinding,

winarea/draw.c

@@ -2,14 +2,7 @@
 #include "area.h"
 
 struct uiDrawContext {
-	HDC mainDC;
+	HDC dc;
-
-	// when drawing in RGBA mode, we need to use this
-	HDC alphaDC;
-	HBITMAP alphaBitmap;
-
-	// and this is the DC we actually draw to, either mainDC or alphaDC
-	HDC currentDC;
 
 	// source color
 	BOOL useRGB;
@@ -25,7 +18,7 @@ uiDrawContext *newContext(HDC dc)
 	uiDrawContext *c;
 
 	c = (uiDrawContext *) g_malloc0(sizeof (uiDrawContext));
-	c->mainDC = dc;
+	c->dc = dc;
 	return c;
 }
 
@@ -36,31 +29,37 @@ void uiDrawBeginPathRGB(uiDrawContext *c, uint8_t r, uint8_t g, uint8_t b)
 	c->r = r;
 	c->g = g;
 	c->b = b;
-	c->currentDC = c->mainDC;
+	if (BeginPath(c->dc) == 0)
-	if (BeginPath(c->currentDC) == 0)
 		logLastError("error beginning new path in uiDrawBeginPathRGB()");
 }
 
 void uiDrawBeginPathRGBA(uiDrawContext *c, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
 {
-	// TODO
+	c->useRGB = TRUE;
+	c->useAlpha = TRUE;
+	c->r = r;
+	c->g = g;
+	c->b = b;
+	c->a = a;
+	if (BeginPath(c->dc) == 0)
+		logLastError("error beginning new path in uiDrawBeginPathRGB()");
 }
 
 void uiDrawMoveTo(uiDrawContext *c, intmax_t x, intmax_t y)
 {
-	if (MoveToEx(c->currentDC, x, y, NULL) == 0)
+	if (MoveToEx(c->dc, x, y, NULL) == 0)
 		logLastError("error moving to point in uiDrawMoveTo()");
 }
 
 void uiDrawLineTo(uiDrawContext *c, intmax_t x, intmax_t y)
 {
-	if (LineTo(c->currentDC, x, y) == 0)
+	if (LineTo(c->dc, x, y) == 0)
 		logLastError("error drawing line in uiDrawLineTo()");
 }
 
 void uiDrawRectangle(uiDrawContext *c, intmax_t x, intmax_t y, intmax_t width, intmax_t height)
 {
-	if (Rectangle(c->currentDC, x, y, x + width, y + height) == 0)
+	if (Rectangle(c->dc, x, y, x + width, y + height) == 0)
 		logLastError("error drawing rectangle in uiDrawRectangle()");
 }
 
@@ -70,7 +69,7 @@ void uiDrawArc(uiDrawContext *c, intmax_t xCenter, intmax_t yCenter, intmax_t ra
 		// TODO
 	}
 	// TODO convert radians to degrees
-	if (AngleArc(c->currentDC,
+	if (AngleArc(c->dc,
 		xCenter, yCenter
 		radius,
 		startAngle,
@@ -79,42 +78,266 @@ void uiDrawArc(uiDrawContext *c, intmax_t xCenter, intmax_t yCenter, intmax_t ra
 		logLastError("error drawing arc in uiDrawArc()");
 }
 
+void uiDrawBezierTo(uiDrawContext *c, intmax_t c1x, intmax_t c1y, intmax_t c2x, intmax_t c2y, intmax_t endX, intmax_t endY)
+{
+	POINT points[3];
+
+	points[0].x = c1x;
+	points[0].y = c1y;
+	points[1].x = c2x;
+	points[2].y = c2y;
+	points[3].x = endX;
+	points[3].y = endY;
+	if (PolyBezierTo(c->dc, points, 3) == 0)
+		logLastError("error drawing bezier curve in uiDrawBezierTo()");
+}
+
 void uiDrawCloseFigure(uiDrawContext *c)
 {
 	if (CloseFigure(c->currentDC) == 0)
 		logLastError("error closing figure in uiDrawCloseFigure()");
 }
 
-void uiDrawStroke(uiDrawContext *c, uiDrawStrokeParams *p)
+static HPEN toPen(uiDrawContext *c, uiDrawStrokeParams *p)
 {
-	// TODO
+	DWORD style;
+	LOGBRUSH lb;
+	HPEN pen;
 
+	style = PS_GEOMETRIC;
 	switch (p->Cap) {
 	case uiDrawLineCapFlat:
+		style |= PS_ENDCAP_FLAT;
 		break;
 	case uiDrawLineCapRound:
+		style |= PS_ENDCAP_ROUND;
 		break;
 	case uiDrawLineCapSquare:
+		style |= PS_ENDCAP_SQUARE;
 		break;
 	}
 	switch (p->Join) {
 	case uiDrawLineJoinMiter:
+		style |= PS_JOIN_MITER;
 		break;
 	case uiDrawLineJoinRound:
+		style |= PS_JOIN_ROUND;
 		break;
 	case uiDrawLineJoinBevel:
+		style |= PS_JOIN_BEVEL;
 		break;
 	}
+	ZeroMemory(&lb, sizeof (LOGBRUSH));
+	if (c->useRGB) {
+		lb.lbStyle = BS_SOLID;
+		// we don't need to worry about alpha premultiplication; see below
+		lb.lbColor = RGB(c->r, c->g, c->b);
+	} else {
+		// TODO
+	}
+	pen = ExtCreatePen(style,
+		p->Thickness,
+		&lb,
+		0,
+		NULL);
+	if (pen == NULL)
+		logLastError("error creating pen in toPen()");
+	return pen;
+}
+
+// unfortunately alpha blending in GDI is limited to bitmap on bitmap
+// to do alpha vector graphics, we have to fake it by drawing to an offscreen bitmap first
+// also we can't just use regions, we have to copy the path...
+// we don't need to worry about alpha premultiplication; see below
+struct alpha {
+	HDC dc;
+	HBITMAP bitmap;
+	VOID *ppvBits;
+	HBITMAP prevbitmap;
+	RECT r;
+};
+
+static void startAlpha(uiDrawContext *c, struct alpha *a)
+{
+	int n;
+	POINT *points;
+	BYTE *ops;
+	HRGN region;
+	BITMAPINFO bi;
+	DWORD le;
+
+	ZeroMemory(a, sizeof (struct alpha));
+
+	// first, get the path
+	// we need to do this first because PathToRegion() clears the path
+	SetLastError(0);
+	n = GetPath(c->dc, NULL, NULL, 0);
+	if (n == 0) {
+		le = GetLastError();
+		SetLastError(le);		// just in case
+		if (le != 0)
+			logLastError("error getting path point count in startAlpha()");
+	}
+	// TODO switch to uiAlloc
+	points = (POINT *) malloc(n * sizeof (POINT));
+	ops = (BYTE *) malloc(n * sizeof (BYTE));
+	if (GetPath(c->dc, points, ops, n) != n)
+		logLastError("error getting path in startAlpha()");
+
+	// next we need to know the bounding box of the path so we can create the bitmap
+	region = PathToRegion(c->dc);
+	if (region == NULL)
+		logLastError("error getting path region in startAlpha()");
+	if (GetRgnBox(region, &(a->r)) == 0)
+		logLastError("error getting region bounding box in startAlpha()");
+	if (DeleteObject(region) == 0)
+		logLastError("error deleting path region in startAlpha()");
+
+	// now create a DC compatible with the original that we can copy the path to and AlphaBlend() from
+	a->dc = CreateCompatibleDC(c->dc);
+	if (a->dc == NULL)
+		logLastError("error creating compatible DC in startAlpha()");
+
+	// now create and select in a *device-independent* bitmap that will hold the data that we're going to alpha blend
+	ZeroMemory(&bmi, sizeof (BITMAPINFO));
+	bi.bmiHeader.biSize = sizeof (BITMAPINFOHEADER);
+	bi.bmiHeader.biWidth = a->r.right - a->r.left;
+	bi.bmiHeader.biHeight = -(a->r.bottom - a->r.top);		// negative to draw top-down
+	bi.bmiHeader.biPlanes = 1;
+	bi.bmiHeader.biBitCount = 32;
+	bi.bmiHeader.biCompression = BI_RGB;
+	a->bitmap = CreateDIBSection(c->dc, &bi, DIB_RGB_COLORS,
+		&(a->ppvBits), NULL, 0);
+	if (a->bitmap == NULL)
+		logLastError("error creating bitmap in startAlpha()");
+	a->prevbitmap = SelectObject(a->dc, a->bitmap);
+	if (a->prevbitmap == NULL)
+		logLastError("error selecting bitmap into DC in startAlpha()");
+
+	// now we can finally copy the path like we were going to earlier
+	if (BeginPath(a->dc) == 0)
+		logLastError("error beginning path in startAlpha()");
+	if (PolyDraw(a->dc, points, ops, n) != 0)
+		logLastError("error copying path in startAlpha()");
+	if (EndPath(a->dc) == 0)
+		logLastError("error ending path in startAlpha()");
+	free(points);
+	free(ops);
+}
+
+static void finishAlpha(uiDrawContext *c, struct alpha *a)
+{
+	BLENDFUNCTION bf;
+
+	bf.BlendOp = AC_SRC_OVER;
+	bf.BlendFlags = 0;
+
+	// fortunately blending this is easy; we don't have to touch the pixels at all because BLENDFUNCTION has a way to take care of this...
+	bf.SourceConstantAlpha = c->a;
+	bf.AlphaFormat = 0;		// no per-pixel apha
+	// a consequence of this setup is that the image data doesn't need to be alpha-premultiplied, because SourceConstantAlpha will be multiplied for us (according to the docs, anyway)
+	// TODO is this actually the case?
+
+	// and we can finally alpha-blend this!
+	if (AlphaBlend(c->dc, a->r.left, a->r.top,
+		a->r.right - a->r.left, a->r.bottom - a->r.top,
+		a->dc, 0, 0,
+		a->r.right - a->r.left, a->r.bottom - a->r.top,
+		bf) == FALSE)
+		logLastError("error alpha blending in finishAlpha()");
+
+	// and clean it all up
+	if (SelectObject(a->dc, a->prevbitmap) != a->bitmap)
+		logLastError("error deselecting bitmap in finishAlpha()");
+	if (DeleteObject(a->bitmap) == 0)
+		logLastError("error deleting object in finishAlpha()");
+	if (DeleteDC(a->dc) == 0)
+		logLastError("error deleting DC in finishAlpha()");
+}
+
+void uiDrawStroke(uiDrawContext *c, uiDrawStrokeParams *p)
+{
+	HPEN pen, prevpen;
+	HDC strokeDC;
+	struct alpha alpha;
+
+	if (EndPath(c->dc) == 0)
+		logLastError("error ending path in uiDrawStroke()");
+
+	if (c->useAlpha) {
+		startAlpha(c, &alpha);
+		strokeDC = alpha.dc;
+	} else		// no alpha; just stroke directly
+		strokeDC = c->dc;
+
+	pen = toPen(c, p);
+	if (p->Join == uiDrawLineJoinMiter)
+		if (SetMiterLimit(strokeDC, p->MiterLimit, NULL) == 0)
+			logLastError("error setting miter limit in uiDrawStroke()");
+	prevpen = SelectObject(strokeDC, pen);
+	if (prevpen == NULL)
+		logLastError("error selecting pen into DC in uiDrawStroke()");
+	if (StrokePath(strokeDC) == 0)
+		logLastError("error stroking path in uiDrawStroke()");
+	if (SelectObject(strokeDC, prevpen) != pen)
+		logLastError("error deselecting pen from DC in uiDrawStroke()");
+	if (DeleteObject(pen) == 0)
+		logLastError("error deleting pen in uiDrawStroke()");
+
+	if (c->useAlpha)
+		finishAlpha(c, &alpha);
+}
+
+static HBRUSH toBrush(uiDrawContext *c)
+{
+	HBRUSH brush;
+
+	if (c->useRGB) {
+		brush = CreateSolidBrush(RGB(c->r, c->g, c->b));
+		if (brush == NULL)
+			logLastError("error creating solid brush in toBrush()");
+		return brush;
+	}
+	// TODO
 }
 
 void uiDrawFill(uiDrawContext *c, uiDrawFillMode mode)
 {
-	// TODO
+	HBRUSH brush, prevbrush;
+	HDC fillDC;
+	struct alpha alpha;
+	int pfm;
+
+	if (EndPath(c->dc) == 0)
+		logLastError("error ending path in uiDrawFill()");
+
+	if (c->useAlpha) {
+		startAlpha(c, &alpha);
+		fillDC = alpha.dc;
+	} else		// no alpha; just stroke directly
+		fillDC = c->dc;
 
 	switch (mode) {
 	case uiDrawFillModeWinding:
+		pfm = WINDING;
 		break;
 	case uiDrawFillModeAlternate:
+		pfm = ALTERNATE;
 		break;
 	}
+	if (SetPolyFillMode(fillDC, pfm) == 0)
+		logLastError("error setting fill mode in uiDrawFill()");
+	brush = toBrush(c);
+	prevbrush = SelectObject(fillDC, brush);
+	if (prevbrush == NULL)
+		logLastError("error selecting brush into DC in uiDrawFill()");
+	if (FillPath(fillDC) == 0)
+		logLastError("error filling path in uiDrawFill()");
+	if (SelectObject(strokeDC, prevbrush) != brush)
+		logLastError("error deselecting brush from DC in uiDrawFill()");
+	if (DeleteObject(brush) == 0)
+		logLastError("error deleting pen in uiDrawStroke()");
+
+	if (c->useAlpha)
+		finishAlpha(c, &alpha);
 }

winarea/ui.h

@@ -56,7 +56,6 @@ enum uiDrawLineJoin {
 #define uiDrawDefaultMiterLimit 10.0
 
 // TODOs
-// - windows: SetPolyFillMode
 // - os x: FillPath/EOFillPath functions
 enum uiDrawFillMode {
 	uiDrawFillModeWinding,