gdiplus: Rendering of linecaps.

dlls/gdiplus/graphics.c

@@ -27,8 +27,11 @@
 #include "gdiplus_private.h"
 #include "wine/debug.h"
 
-/* looks-right constant */
+WINE_DEFAULT_DEBUG_CHANNEL(gdiplus);
+
+/* looks-right constants */
 #define TENSION_CONST (0.3)
+#define ANCHOR_WIDTH (2.0)
 
 static inline INT roundr(REAL x)
 {
@@ -108,6 +111,212 @@ static void calc_curve_bezier_endp(REAL xend, REAL yend, REAL xadj, REAL yadj,
     *y = roundr(tension * (yadj - yend) + yend);
 }
 
+/* Draws the linecap the specified color and size on the hdc.  The linecap is in
+ * direction of the line from x1, y1 to x2, y2 and is anchored on x2, y2. */
+static void draw_cap(HDC hdc, COLORREF color, GpLineCap cap, REAL size,
+    REAL x1, REAL y1, REAL x2, REAL y2)
+{
+    HGDIOBJ oldbrush, oldpen;
+    HBRUSH brush;
+    HPEN pen;
+    POINT pt[4];
+    REAL theta, dsmall, dbig, dx, dy, invert;
+
+    if(x2 != x1)
+        theta = atan((y2 - y1) / (x2 - x1));
+    else if(y2 != y1){
+        theta = M_PI_2 * (y2 > y1 ? 1.0 : -1.0);
+    }
+    else
+        return;
+
+    invert = ((x2 - x1) >= 0.0 ? 1.0 : -1.0);
+    brush = CreateSolidBrush(color);
+    pen = CreatePen(PS_SOLID, 1, color);
+    oldbrush = SelectObject(hdc, brush);
+    oldpen = SelectObject(hdc, pen);
+
+    switch(cap){
+        case LineCapFlat:
+            break;
+        case LineCapSquare:
+        case LineCapSquareAnchor:
+        case LineCapDiamondAnchor:
+            size = size * (cap & LineCapNoAnchor ? ANCHOR_WIDTH : 1.0) / 2.0;
+            if(cap == LineCapDiamondAnchor){
+                dsmall = cos(theta + M_PI_2) * size;
+                dbig = sin(theta + M_PI_2) * size;
+            }
+            else{
+                dsmall = cos(theta + M_PI_4) * size;
+                dbig = sin(theta + M_PI_4) * size;
+            }
+
+            /* calculating the latter points from the earlier points makes them
+             * look a little better because of rounding issues */
+            pt[0].x = roundr(x2 - dsmall);
+            pt[1].x = roundr(((REAL)pt[0].x) + dbig + dsmall);
+
+            pt[0].y = roundr(y2 - dbig);
+            pt[3].y = roundr(((REAL)pt[0].y) + dsmall + dbig);
+
+            pt[1].y = roundr(y2 - dsmall);
+            pt[2].y = roundr(dbig + dsmall + ((REAL)pt[1].y));
+
+            pt[3].x = roundr(x2 - dbig);
+            pt[2].x = roundr(((REAL)pt[3].x) + dsmall + dbig);
+
+            Polygon(hdc, pt, 4);
+
+            break;
+        case LineCapArrowAnchor:
+            size = size * 4.0 / sqrt(3.0);
+
+            dx = cos(M_PI / 6.0 + theta) * size * invert;
+            dy = sin(M_PI / 6.0 + theta) * size * invert;
+
+            pt[0].x = roundr(x2 - dx);
+            pt[0].y = roundr(y2 - dy);
+
+            dx = cos(- M_PI / 6.0 + theta) * size * invert;
+            dy = sin(- M_PI / 6.0 + theta) * size * invert;
+
+            pt[1].x = roundr(x2 - dx);
+            pt[1].y = roundr(y2 - dy);
+
+            pt[2].x = roundr(x2);
+            pt[2].y = roundr(y2);
+
+            Polygon(hdc, pt, 3);
+
+            break;
+        case LineCapRoundAnchor:
+            dx = dy = ANCHOR_WIDTH * size / 2.0;
+
+            x2 = (REAL) roundr(x2 - dx);
+            y2 = (REAL) roundr(y2 - dy);
+
+            Ellipse(hdc, (INT) x2, (INT) y2, roundr(x2 + 2.0 * dx),
+                roundr(y2 + 2.0 * dy));
+            break;
+        case LineCapTriangle:
+            size = size / 2.0;
+            dx = cos(M_PI_2 + theta) * size;
+            dy = sin(M_PI_2 + theta) * size;
+
+            /* Using roundr here can make the triangle float off the end of the
+             * line. */
+            pt[0].x = ((x2 - x1) >= 0 ? floor(x2 - dx) : ceil(x2 - dx));
+            pt[0].y = ((y2 - y1) >= 0 ? floor(y2 - dy) : ceil(y2 - dy));
+            pt[1].x = roundr(pt[0].x + 2.0 * dx);
+            pt[1].y = roundr(pt[0].y + 2.0 * dy);
+
+            dx = cos(theta) * size * invert;
+            dy = sin(theta) * size * invert;
+
+            pt[2].x = roundr(x2 + dx);
+            pt[2].y = roundr(y2 + dy);
+
+            Polygon(hdc, pt, 3);
+
+            break;
+        case LineCapRound:
+            dx = -cos(M_PI_2 + theta) * size * invert;
+            dy = -sin(M_PI_2 + theta) * size * invert;
+
+            pt[0].x = ((x2 - x1) >= 0 ? floor(x2 - dx) : ceil(x2 - dx));
+            pt[0].y = ((y2 - y1) >= 0 ? floor(y2 - dy) : ceil(y2 - dy));
+            pt[1].x = roundr(pt[0].x + 2.0 * dx);
+            pt[1].y = roundr(pt[0].y + 2.0 * dy);
+
+            dx = dy = size / 2.0;
+
+            x2 = (REAL) roundr(x2 - dx);
+            y2 = (REAL) roundr(y2 - dy);
+
+            Pie(hdc, (INT) x2, (INT) y2, roundr(x2 + 2.0 * dx),
+                roundr(y2 + 2.0 * dy), pt[0].x, pt[0].y, pt[1].x, pt[1].y);
+            break;
+        case LineCapCustom:
+            FIXME("line cap not implemented\n");
+        default:
+            break;
+    }
+
+    SelectObject(hdc, oldbrush);
+    SelectObject(hdc, oldpen);
+    DeleteObject(brush);
+    DeleteObject(pen);
+}
+
+/* Shortens the line by the given percent by changing x2, y2.
+ * If percent is > 1.0 then the line will change direction. */
+static void shorten_line_percent(REAL x1, REAL  y1, REAL *x2, REAL *y2, REAL percent)
+{
+    REAL dist, theta, dx, dy;
+
+    if((y1 == *y2) && (x1 == *x2))
+        return;
+
+    dist = sqrt((*x2 - x1) * (*x2 - x1) + (*y2 - y1) * (*y2 - y1)) * percent;
+    theta = (*x2 == x1 ? M_PI_2 : atan((*y2 - y1) / (*x2 - x1)));
+    dx = cos(theta) * dist;
+    dy = sin(theta) * dist;
+
+    *x2 = *x2 + fabs(dx) * (*x2 > x1 ? -1.0 : 1.0);
+    *y2 = *y2 + fabs(dy) * (*y2 > y1 ? -1.0 : 1.0);
+}
+
+/* Shortens the line by the given amount by changing x2, y2.
+ * If the amount is greater than the distance, the line will become length 0. */
+static void shorten_line_amt(REAL x1, REAL y1, REAL *x2, REAL *y2, REAL amt)
+{
+    REAL dx, dy, percent;
+
+    dx = *x2 - x1;
+    dy = *y2 - y1;
+    if(dx == 0 && dy == 0)
+        return;
+
+    percent = amt / sqrt(dx * dx + dy * dy);
+    if(percent >= 1.0){
+        *x2 = x1;
+        *y2 = y1;
+        return;
+    }
+
+    shorten_line_percent(x1, y1, x2, y2, percent);
+}
+
+/* Draws lines between the given points, and if caps is true then draws an endcap
+ * at the end of the last line.  FIXME: Startcaps not implemented. */
+static void draw_polyline(HDC hdc, GpPen *pen, GDIPCONST GpPointF * pt,
+    INT count, BOOL caps)
+{
+    POINT *pti = GdipAlloc(count * sizeof(POINT));
+    REAL x = pt[count - 1].X, y = pt[count - 1].Y;
+    INT i;
+
+    if(caps){
+        if(pen->endcap == LineCapArrowAnchor)
+            shorten_line_amt(pt[count-2].X, pt[count-2].Y, &x, &y, pen->width);
+
+        draw_cap(hdc, pen->color, pen->endcap, pen->width, pt[count-2].X,
+            pt[count-2].Y, pt[count - 1].X, pt[count - 1].Y);
+    }
+
+    for(i = 0; i < count - 1; i ++){
+        pti[i].x = roundr(pt[i].X);
+        pti[i].y = roundr(pt[i].Y);
+    }
+
+    pti[i].x = roundr(x);
+    pti[i].y = roundr(y);
+
+    Polyline(hdc, pti, count);
+    GdipFree(pti);
+}
+
 GpStatus WINGDIPAPI GdipCreateFromHDC(HDC hdc, GpGraphics **graphics)
 {
     if(hdc == NULL)
@@ -248,16 +457,21 @@ GpStatus WINGDIPAPI GdipDrawLineI(GpGraphics *graphics, GpPen *pen, INT x1,
     INT y1, INT x2, INT y2)
 {
     INT save_state;
+    GpPointF pt[2];
 
     if(!pen || !graphics)
         return InvalidParameter;
 
+    pt[0].X = (REAL)x1;
+    pt[0].Y = (REAL)y1;
+    pt[1].X = (REAL)x2;
+    pt[1].Y = (REAL)y2;
+
     save_state = SaveDC(graphics->hdc);
     EndPath(graphics->hdc);
     SelectObject(graphics->hdc, pen->gdipen);
 
-    MoveToEx(graphics->hdc, x1, y1, NULL);
+    draw_polyline(graphics->hdc, pen, pt, 2, TRUE);
-    LineTo(graphics->hdc, x2, y2);
 
     RestoreDC(graphics->hdc, save_state);
 

dlls/gdiplus/pen.c

@@ -77,11 +77,6 @@ GpStatus WINGDIPAPI GdipSetPenEndCap(GpPen *pen, GpLineCap cap)
 {
     if(!pen)    return InvalidParameter;
 
-    if(cap != LineCapFlat){
-        FIXME("Not implemented for non-flat EndCap\n");
-        return NotImplemented;
-    }
-
     pen->endcap = cap;
 
     return Ok;