ae53754392371fb4f12ce622b5ccaf79321d0556
kate
  Mon Mar 12 15:29:40 2018 -0700
Curve function returns max y drawn (helps max box placement). refs #17512

diff --git src/hg/lib/hvGfx.c src/hg/lib/hvGfx.c
index cef8423..6ec4c60 100644
--- src/hg/lib/hvGfx.c
+++ src/hg/lib/hvGfx.c
@@ -1,473 +1,496 @@
 /* hvGfx - browser graphics interface.  This is a thin layer on top of vGfx
  * providing genome browser-specific features.  It was added to handle
  * reverse-complement display. */
 
 /* Copyright (C) 2014 The Regents of the University of California 
  * See README in this or parent directory for licensing information. */
 
 #include "common.h"
 #include "hvGfx.h"
 #include "obscure.h"
 
 
 static struct hvGfx *hvGfxAlloc(struct vGfx *vg)
 /* allocate a hvgGfx object */
 {
 struct hvGfx *hvg;
 AllocVar(hvg);
 hvg->vg = vg;
 hvg->pixelBased = vg->pixelBased;
 hvg->width = vg->width;
 hvg->height = vg->height;
 hvg->clipMaxX = vg->width;
 hvg->clipMaxY = vg->height;
 return hvg;
 }
 
 struct hvGfx *hvGfxOpenPng(int width, int height, char *fileName, boolean useTransparency)
 /* Open up something that we'll write out as a PNG someday. */
 {
 return hvGfxAlloc(vgOpenPng(width, height, fileName, useTransparency));
 }
 
 struct hvGfx *hvGfxOpenPostScript(int width, int height, char *fileName)
 /* Open up something that will someday be a PostScript file. */
 {
 return hvGfxAlloc(vgOpenPostScript(width, height, fileName));
 }
 
 void hvGfxClose(struct hvGfx **pHvg)
 /* Close down virtual graphics object, and finish writing it to file. */
 {
 struct hvGfx *hvg = *pHvg;
 if (hvg != NULL)
     {
     vgClose(&hvg->vg);
     freez(pHvg);
     }
 }
 
 void hvGfxMakeColorGradient(struct hvGfx *hvg, 
                             struct rgbColor *start, struct rgbColor *end,
                             int steps, Color *colorIxs)
 /* Make a color gradient that goes smoothly from start to end colors in given
  * number of steps.  Put indices in color table in colorIxs */
 {
 double scale = 0, invScale;
 double invStep;
 int i;
 int r,g,b;
 
 steps -= 1;	/* Easier to do the calculation in an inclusive way. */
 invStep = 1.0/steps;
 for (i=0; i<=steps; ++i)
     {
     invScale = 1.0 - scale;
     r = invScale * start->r + scale * end->r;
     g = invScale * start->g + scale * end->g;
     b = invScale * start->b + scale * end->b;
     colorIxs[i] = hvGfxFindColorIx(hvg, r, g, b);
     scale += invStep;
     }
 }
 
 static long figureTickSpan(long totalLength, int maxNumTicks)
 /* Figure out whether ticks on ruler should be 1, 5, 10, 50, 100, 500, 
  * 1000, etc. units apart.  */
 {
 int roughTickLen = totalLength/maxNumTicks;
 int i;
 int tickLen = 1;
 
 for (i=0; i<9; ++i)
     {
     if (roughTickLen < tickLen)
     	return tickLen;
     tickLen *= 5;
     if (roughTickLen < tickLen)
 	return tickLen;
     tickLen *= 2;
     }
 return 1000000000;
 }
 
 void hvGfxDrawRulerBumpText(struct hvGfx *hvg, int xOff, int yOff, 
 	int height, int width,
         Color color, MgFont *font,
         int startNum, int range, int bumpX, int bumpY)
 /* Draw a ruler inside the indicated part of mg with numbers that start at
  * startNum and span range.  Bump text positions slightly. */
 {
 int tickSpan;
 int tickPos;
 double scale;
 int firstTick;
 int remainder;
 int end = startNum + range;
 int x;
 char tbuf[18];
 int numWid;
 int goodNumTicks;
 int niceNumTicks = width/35;
 
 sprintLongWithCommas(tbuf, startNum+range);
 numWid = mgFontStringWidth(font, tbuf)+4+bumpX;
 goodNumTicks = width/numWid;
 if (goodNumTicks < 1) goodNumTicks = 1;
 if (goodNumTicks > niceNumTicks) goodNumTicks = niceNumTicks;
 
 tickSpan = figureTickSpan(range, goodNumTicks);
 
 scale = (double)width / range;
 
 firstTick = startNum + tickSpan;
 remainder = firstTick % tickSpan;
 firstTick -= remainder;
 for (tickPos=firstTick; tickPos<end; tickPos += tickSpan)
     {
     sprintLongWithCommas(tbuf, tickPos);
     numWid = mgFontStringWidth(font, tbuf)+4;
     x = (int)((tickPos-startNum) * scale) + xOff;
     hvGfxBox(hvg, x, yOff, 1, height, color);
     if (x - numWid >= xOff)
         {
         hvGfxTextCentered(hvg, x-numWid + bumpX, yOff + bumpY, numWid, 
                           height, color, font, tbuf);
         }
     }
 }
 
 void hvGfxDrawRuler(struct hvGfx *hvg, int xOff, int yOff, int height, int width,
         Color color, MgFont *font,
         int startNum, int range)
 /* Draw a ruler inside the indicated part of mg with numbers that start at
  * startNum and span range.  */
 {
 hvGfxDrawRulerBumpText(hvg, xOff, yOff, height, width, color, font,
                        startNum, range, 0, 0);
 }
 
 
 void hvGfxBarbedHorizontalLine(struct hvGfx *hvg, int x, int y, 
 	int width, int barbHeight, int barbSpacing, int barbDir, Color color,
 	boolean needDrawMiddle)
 /* Draw a horizontal line starting at xOff, yOff of given width.  Will
  * put barbs (successive arrowheads) to indicate direction of line.  
  * BarbDir of 1 points barbs to right, of -1 points them to left. */
 {
 barbDir = (hvg->rc) ? -barbDir : barbDir;
 if (barbDir == 0)
     return;  // fully clipped, or no barbs
 x = hvGfxAdjXW(hvg, x, width);
 int x1, x2;
 int yHi, yLo;
 int offset, startOffset, endOffset, barbAdd;
 int scrOff = (barbSpacing - 1) - (x % (barbSpacing));
 
 yHi = y + barbHeight;
 yLo = y - barbHeight;
 if (barbDir < 0)
     {
     startOffset = scrOff - barbHeight;
     startOffset = (startOffset >= 0) ?startOffset : 0;
     endOffset = width - barbHeight;
     barbAdd = barbHeight;
     }
 else
     {
     startOffset = scrOff + barbHeight;
     endOffset = width;
     barbAdd = -barbHeight;
     }
 
 for (offset = startOffset; offset < endOffset; offset += barbSpacing)
     {
     x1 = x + offset;
     x2 = x1 + barbAdd;
     vgLine(hvg->vg, x1, y, x2, yHi, color);
     vgLine(hvg->vg, x1, y, x2, yLo, color);
     }
 }
 
 void hvGfxNextItemButton(struct hvGfx *hvg, int x, int y, int w, int h, 
 		      Color color, Color hvgColor, boolean nextItem)
 /* Draw a button that looks like a fast-forward or rewind button on */
 /* a remote control. If nextItem is TRUE, it points right, otherwise */
 /* left. color is the outline color, and hvgColor is the fill color. */
 {
 x = hvGfxAdjXW(hvg, x, w);
 if (hvg->rc)
     nextItem = !nextItem;
 
 struct gfxPoly *t1, *t2;
 /* Make the triangles */
 t1 = gfxPolyNew();
 t2 = gfxPolyNew();
 if (nextItem)
     /* point right. */
     {
     gfxPolyAddPoint(t1, x, y);
     gfxPolyAddPoint(t1, x+w/2, y+h/2);
     gfxPolyAddPoint(t1, x, y+h);
     gfxPolyAddPoint(t2, x+w/2, y);
     gfxPolyAddPoint(t2, x+w, y+h/2);
     gfxPolyAddPoint(t2, x+w/2, y+h);    
     }
 else
     /* point left. */
     {
     gfxPolyAddPoint(t1, x, y+h/2);
     gfxPolyAddPoint(t1, x+w/2, y);
     gfxPolyAddPoint(t1, x+w/2, y+h);
     gfxPolyAddPoint(t2, x+w/2, y+h/2);
     gfxPolyAddPoint(t2, x+w, y);
     gfxPolyAddPoint(t2, x+w, y+h);
     }
 /* The two filled triangles. */
 vgDrawPoly(hvg->vg, t1, hvgColor, TRUE);
 vgDrawPoly(hvg->vg, t2, hvgColor, TRUE);
 /* The two outline triangles. */
 vgDrawPoly(hvg->vg, t1, color, FALSE);
 vgDrawPoly(hvg->vg, t2, color, FALSE);
 gfxPolyFree(&t1);
 gfxPolyFree(&t2);
 }
 
 /* from memgfx.c and vPng.c*/
 
 struct memPng
 /* Something that handles a PNG. */
     {
     struct memGfx mg;	/* Memory form.  This needs to be first field. */
     char *fileName;	/* PNG file name. */
     boolean useTransparency;   /* Make background color transparent if TRUE. */
     };
 
 #define _mgBpr(mg) ((mg)->width)
 #define _mgPixAdr(mg,x,y) ((mg)->pixels+_mgBpr(mg) * (y) + (x))
 
 INLINE void mixDot(struct hvGfx *hvg, int x, int y,  float frac, Color col)
 /* Puts a single dot on the image, mixing it with what is already there
  * based on the frac argument. */
 {
 struct memPng *png = (struct memPng *)hvg->vg->data;
 struct memGfx *img = (struct memGfx *)png;
 if ((x < img->clipMinX) || (x > img->clipMaxX) || (y < img->clipMinY) || (y > img->clipMaxY))
     return;
 
 Color *pt = _mgPixAdr(img,x,y);
 float invFrac = 1 - frac;
 
 int r = COLOR_32_RED(*pt) * invFrac + COLOR_32_RED(col) * frac;
 int g = COLOR_32_GREEN(*pt) * invFrac + COLOR_32_GREEN(col) * frac;
 int b = COLOR_32_BLUE(*pt) * invFrac + COLOR_32_BLUE(col) * frac;
 hvGfxDot(hvg, x, y, MAKECOLOR_32(r,g,b));
 hvGfxDot(hvg, x, y, MAKECOLOR_32(r,g,b));
 }
 
 void hvGfxDottedLine(struct hvGfx *hvg, int x1, int y1, int x2, int y2, Color color, boolean isDash)
 /* Brezenham line algorithm, alternating dots, by 1 pixel or two (isDash true) */
 {   
 int duty_cycle;
 int incy;
 int delta_x, delta_y;
 int dots;
 int dotFreq = (isDash ? 3 : 2);
 delta_y = y2-y1;
 delta_x = x2-x1;
 if (delta_y < 0)  
     {   
     delta_y = -delta_y;
     incy = -1; 
     }   
 else
     {   
     incy = 1;
     }   
 if (delta_x < 0)  
     {   
     delta_x = -delta_x;
     incy = -incy;
     x1 = x2; 
     y1 = y2; 
     }   
 duty_cycle = (delta_x - delta_y)/2;
 if (delta_x >= delta_y)
     {   
     dots = delta_x+1;
     while (--dots >= 0)
         {   
         if (dots % dotFreq)
             hvGfxDot(hvg,x1,y1,color);
         duty_cycle -= delta_y;
         x1 += 1;
         if (duty_cycle < 0)
             {   
             duty_cycle += delta_x;        /* update duty cycle */
             y1+=incy;
             }   
         }   
     }   
 else
     {   
     dots = delta_y+1;
     while (--dots >= 0)
         {   
         if (dots % dotFreq)
             hvGfxDot(hvg,x1,y1,color);
         duty_cycle += delta_x;
         y1+=incy;
         if (duty_cycle > 0)
             {   
             duty_cycle -= delta_y;        /* update duty cycle */
             x1 += 1;
             }   
         }   
     }   
 }   
 
-void hvGfxCurveSegAA(struct hvGfx *hvg, int x0, int y0, int x1, int y1, int x2, int y2, 
+int hvGfxCurveSegAA(struct hvGfx *hvg, int x0, int y0, int x1, int y1, int x2, int y2, 
                         Color color, boolean isDashed)
 /* Draw a segment of an anti-aliased curve within 3 points (quadratic Bezier)
- * Optionally alternate dots.
+ * Return max y value. Optionally alternate dots.
  * Adapted trivially from code posted on github and at http://members.chello.at/~easyfilter/bresenham.html */
  /* Thanks to author  * @author Zingl Alois
  * @date 22.08.2016 */
 {
+   int yMax = 0;
    int sx = x2-x1, sy = y2-y1;
    long xx = x0-x1, yy = y0-y1, xy;             /* relative values for checks */
    double dx, dy, err, ed, cur = xx*sy-yy*sx;                    /* curvature */
 
    assert(xx*sx <= 0 && yy*sy <= 0);      /* sign of gradient must not change */
 
    if (sx*(long)sx+sy*(long)sy > xx*xx+yy*yy) {     /* begin with longer part */
       x2 = x0; x0 = sx+x1; y2 = y0; y0 = sy+y1; cur = -cur;     /* swap P0 P2 */
    }
    if (cur != 0)
    {                                                      /* no straight line */
       xx += sx; xx *= sx = x0 < x2 ? 1 : -1;              /* x step direction */
       yy += sy; yy *= sy = y0 < y2 ? 1 : -1;              /* y step direction */
       xy = 2*xx*yy; xx *= xx; yy *= yy;             /* differences 2nd degree */
       if (cur*sx*sy < 0) {                              /* negated curvature? */
          xx = -xx; yy = -yy; xy = -xy; cur = -cur;
       }
       dx = 4.0*sy*(x1-x0)*cur+xx-xy;                /* differences 1st degree */
       dy = 4.0*sx*(y0-y1)*cur+yy-xy;
       xx += xx; yy += yy; err = dx+dy+xy;                   /* error 1st step */
       int dots = 0;
       do {
          cur = fmin(dx+xy,-xy-dy);
          ed = fmax(dx+xy,-xy-dy);               /* approximate error distance */
          ed += 2*ed*cur*cur/(4*ed*ed+cur*cur);
          if (!isDashed || (++dots % 3))
+            {
             mixDot(hvg, x0,y0, 1-fabs(err-dx-dy-xy)/ed, color);          /* plot curve */
+            if (y0 > yMax)
+                yMax = y0;
+            }
          if (x0 == x2 || y0 == y2) break;     /* last pixel -> curve finished */
          x1 = x0; cur = dx-err; y1 = 2*err+dy < 0;
          if (2*err+dx > 0) {                                        /* x step */
             if (err-dy < ed) 
+                {
                 mixDot(hvg, x0,y0+sy, 1-fabs(err-dy)/ed, color);
+                if (y0 > yMax)
+                    yMax = y0;
+                }
             x0 += sx; dx -= xy; err += dy += yy;
          }
          if (y1) {                                                  /* y step */
-            if (cur < ed) mixDot(hvg, x1+sx,y0, 1-fabs(cur)/ed, color);
+            if (cur < ed) 
+                {
+                mixDot(hvg, x1+sx,y0, 1-fabs(cur)/ed, color);
+                if (y0 > yMax)
+                    yMax = y0;
+                }
             y0 += sy; dy -= xy; err += dx += xx;
          }
       } while (dy < dx);                  /* gradient negates -> close curves */
    }
    hvGfxLine(hvg, x0,y0, x2,y2, color);                  /* plot remaining needle to end */
+   if (y0 > yMax)
+       yMax = y0;
+   return yMax;
 }
 
-void hvGfxCurve(struct hvGfx *hvg, int x0, int y0, int x1, int y1, int x2, int y2, 
+int hvGfxCurve(struct hvGfx *hvg, int x0, int y0, int x1, int y1, int x2, int y2, 
                         Color color, boolean isDashed)
 /* Draw a segment of an anti-aliased curve within 3 points (quadratic Bezier)
- * Optionally alternate dots.
- * Adapted trivially from code posted at http://members.chello.at/~easyfilter/bresenham.html */
+ * Return max y value. Optionally alternate dots.
+ * Adapted trivially from code posted at http://members.chello.at/~easyfilter/bresenham.html
+ */
 {
    int x = x0-x1, y = y0-y1;
    double t = x0-2*x1+x2, r;
-
+   int yMax = 0, yMaxRet = 0;
    if ((long)x*(x2-x1) > 0) {                        /* horizontal cut at P4? */
       if ((long)y*(y2-y1) > 0)                     /* vertical cut at P6 too? */
          if (fabs((y0-2*y1+y2)/t*x) > abs(y)) {               /* which first? */
             x0 = x2; x2 = x+x1; y0 = y2; y2 = y+y1;            /* swap points */
          }                            /* now horizontal cut at P4 comes first */
       t = (x0-x1)/t;
       r = (1-t)*((1-t)*y0+2.0*t*y1)+t*t*y2;                       /* By(t=P4) */
       t = (x0*x2-x1*x1)*t/(x0-x1);                       /* gradient dP4/dx=0 */
       x = floor(t+0.5); y = floor(r+0.5);
       r = (y1-y0)*(t-x0)/(x1-x0)+y0;                  /* intersect P3 | P0 P1 */
-      hvGfxCurveSegAA(hvg,x0,y0, x,floor(r+0.5), x,y, color, isDashed);
+      yMax = hvGfxCurveSegAA(hvg,x0,y0, x,floor(r+0.5), x,y, color, isDashed);
       r = (y1-y2)*(t-x2)/(x1-x2)+y2;                  /* intersect P4 | P1 P2 */
       x0 = x1 = x; y0 = y; y1 = floor(r+0.5);             /* P0 = P4, P1 = P8 */
    }
    if ((long)(y0-y1)*(y2-y1) > 0) {                    /* vertical cut at P6? */
       t = y0-2*y1+y2; t = (y0-y1)/t;
       r = (1-t)*((1-t)*x0+2.0*t*x1)+t*t*x2;                       /* Bx(t=P6) */
       t = (y0*y2-y1*y1)*t/(y0-y1);                       /* gradient dP6/dy=0 */
       x = floor(r+0.5); y = floor(t+0.5);
       r = (x1-x0)*(t-y0)/(y1-y0)+x0;                  /* intersect P6 | P0 P1 */
-      hvGfxCurveSegAA(hvg,x0,y0, floor(r+0.5),y, x,y, color, isDashed);
+      yMaxRet = hvGfxCurveSegAA(hvg,x0,y0, floor(r+0.5),y, x,y, color, isDashed);
+      if (yMaxRet > yMax)
+        yMax = yMaxRet;
       r = (x1-x2)*(t-y2)/(y1-y2)+x2;                  /* intersect P7 | P1 P2 */
       x0 = x; x1 = floor(r+0.5); y0 = y1 = y;             /* P0 = P6, P1 = P7 */
    }
-   hvGfxCurveSegAA(hvg,x0,y0, x1,y1, x2,y2, color, isDashed); /* remaining part */
+   yMaxRet = hvGfxCurveSegAA(hvg,x0,y0, x1,y1, x2,y2, color, isDashed); /* remaining part */
+   if (yMaxRet > yMax)
+     yMax = yMaxRet;
+   return yMax;
 }
 
 void hvGfxEllipseDraw(struct hvGfx *hvg, int x0, int y0, int x1, int y1, Color color, 
                         int mode, boolean isDashed)
 /* Draw an ellipse (or limit to top or bottom) specified by rectangle, using Bresenham algorithm.
  * Optionally, alternate dots.
  * Point 0 is left, point 1 is top of rectangle
  * Adapted trivially from code posted at http://members.chello.at/~easyfilter/bresenham.html
  */
 {
    int a = abs(x1-x0), b = abs(y1-y0), b1 = b&1; /* values of diameter */
    long dx = 4*(1-a)*b*b, dy = 4*(b1+1)*a*a; /* error increment */
    long err = dx+dy+b1*a*a, e2; /* error of 1.step */
 
    if (x0 > x1) { x0 = x1; x1 += a; } /* if called with swapped points */
    if (y0 > y1) y0 = y1; /* .. exchange them */
    y0 += (b+1)/2; y1 = y0-b1;   /* starting pixel */
    a *= 8*a; b1 = 8*b*b;
 
    int dots = 0;
    do {
        if (!isDashed || (++dots % 3))
            {
            if (mode == ELLIPSE_BOTTOM || mode == ELLIPSE_FULL) 
                {
                hvGfxDot(hvg, x1, y0, color); /*   I. Quadrant */
                hvGfxDot(hvg, x0, y0, color); /*  II. Quadrant */
                }
            if (mode == ELLIPSE_TOP || mode == ELLIPSE_FULL) 
                {
                hvGfxDot(hvg, x0, y1, color); /* III. Quadrant */
                hvGfxDot(hvg, x1, y1, color); /*  IV. Quadrant */
                }
            }
        e2 = 2*err;
        if (e2 <= dy) { y0++; y1--; err += dy += a; }  /* y step */
        if (e2 >= dx || 2*err > dy) { x0++; x1--; err += dx += b1; } /* x step */
    } while (x0 <= x1);
 
    while (y0-y1 < b) {  /* too early stop of flat ellipses a=1 */
        if (!isDashed && (++dots % 3))
            {
            hvGfxDot(hvg, x0-1, y0, color); /* -> finish tip of ellipse */
            hvGfxDot(hvg, x1+1, y0++, color);
            hvGfxDot(hvg, x0-1, y1, color);
            hvGfxDot(hvg, x1+1, y1--, color);
            }
    }
 }
 
 void hvGfxEllipse(struct hvGfx *hvg, int x0, int y0, int x1, int y1, Color color)
 /* Draw a full ellipse specified by rectangle, using Bresenham algorithm.
  * Point 0 is left, point 1 is top of rectangle
  * Adapted trivially from code posted at http://members.chello.at/~easyfilter/bresenham.html
  */
 {
 hvGfxEllipseDraw(hvg, x0, y0, x1, y1, color, ELLIPSE_FULL, FALSE);
 }