interesting
/
libui
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Enhanced the histogram example with some basic mouse interaction.

This commit is contained in:
Pietro Gagliardi 2015-10-14 11:45:31 -04:00
parent 2b4ba6ad16
commit 10cba66bbf
1 changed files with 72 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

87
examples/histogram/main.c
View File

@ -9,12 +9,14 @@ uiWindow *mainwin;
uiArea *histogram;
uiAreaHandler handler;
uiSpinbox *datapoints[10];
int currentPoint = -1;
// some metrics
#define xoffLeft 20 /* histogram margins */
#define yoffTop 20
#define xoffRight 20
#define yoffBottom 20
#define pointRadius 5
// helper to quickly set a brush color
static void setSolidBrush(uiDrawBrush *brush, uint32_t color, double alpha)
@ -37,30 +39,37 @@ static void setSolidBrush(uiDrawBrush *brush, uint32_t color, double alpha)
#define colorBlack 0x000000
#define colorDodgerBlue 0x1E90FF
static uiDrawPath *constructGraph(double width, double height, int extend)
static void pointLocations(double width, double height, double *xs, double *ys)
{
uiDrawPath *path;
double xincr, yincr;
int i, n;
path = uiDrawNewPath(uiDrawFillModeWinding);
xincr = width / 9; // 10 - 1 to make the last point be at the end
yincr = height / 100;
for (i = 0; i < 10; i++) {
// get the value of the point
n = uiSpinboxValue(datapoints[i]);
// because y=0 is the top but n=0 is the bottom, we need to flip
n = 100 - n;
if (i == 0)
uiDrawPathNewFigure(path,
xincr * i,
yincr * n);
else
uiDrawPathLineTo(path,
xincr * i,
yincr * n);
xs[i] = xincr * i;
ys[i] = yincr * n;
}
}
static uiDrawPath *constructGraph(double width, double height, int extend)
{
uiDrawPath *path;
double xs[10], ys[10];
int i;
pointLocations(width, height, xs, ys);
path = uiDrawNewPath(uiDrawFillModeWinding);
uiDrawPathNewFigure(path, xs[0], ys[0]);
for (i = 1; i < 10; i++)
uiDrawPathLineTo(path, xs[i], ys[i]);
if (extend) {
uiDrawPathLineTo(path, width, height);
@ -72,6 +81,12 @@ static uiDrawPath *constructGraph(double width, double height, int extend)
return path;
}
static void graphSize(double clientWidth, double clientHeight, double *graphWidth, double *graphHeight)
{
*graphWidth = clientWidth - xoffLeft - xoffRight;
*graphHeight = clientHeight - yoffTop - yoffBottom;
}
static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
{
uiDrawPath *path;
@ -89,8 +104,7 @@ static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
uiDrawFreePath(path);
// figure out dimensions
graphWidth = p->ClientWidth - xoffLeft - xoffRight;
graphHeight = p->ClientHeight - yoffTop - yoffBottom;
graphSize(p->ClientWidth, p->ClientHeight, &graphWidth, &graphHeight);
// make a stroke for both the axes and the histogram line
sp.Cap = uiDrawLineCapFlat;
@ -127,6 +141,23 @@ static void handlerDraw(uiAreaHandler *a, uiArea *area, uiAreaDrawParams *p)
setSolidBrush(&brush, colorDodgerBlue, 1.0);
uiDrawStroke(p->Context, path, &brush, &sp);
uiDrawFreePath(path);
// now draw the point being hovered over
if (currentPoint != -1) {
double xs[10], ys[10];
pointLocations(graphWidth, graphHeight, xs, ys);
path = uiDrawNewPath(uiDrawFillModeWinding);
uiDrawPathNewFigureWithArc(path,
xs[currentPoint], ys[currentPoint],
pointRadius,
0, 6.23, // TODO pi
0);
uiDrawPathEnd(path);
// use the same brush as for the histogram lines
uiDrawFill(p->Context, path, &brush);
uiDrawFreePath(path);
}
}
static uintmax_t handlerHScrollMax(uiAreaHandler *a, uiArea *area)
@ -147,9 +178,35 @@ static int handlerRedrawOnResize(uiAreaHandler *a, uiArea *area)
return 1;
}
static int inPoint(double x, double y, double xtest, double ytest)
{
// TODO switch to using a matrix
x -= xoffLeft;
y -= yoffTop;
return (x >= xtest - pointRadius) &&
(x <= xtest + pointRadius) &&
(y >= ytest - pointRadius) &&
(y <= ytest + pointRadius);
}
static void handlerMouseEvent(uiAreaHandler *a, uiArea *area, uiAreaMouseEvent *e)
{
// do nothing
double graphWidth, graphHeight;
double xs[10], ys[10];
int i;
graphSize(e->ClientWidth, e->ClientHeight, &graphWidth, &graphHeight);
pointLocations(graphWidth, graphHeight, xs, ys);
for (i = 0; i < 10; i++)
if (inPoint(e->X, e->Y, xs[i], ys[i]))
break;
if (i == 10) // not in a point
i = -1;
currentPoint = i;
// TODO only redraw the relevant area
uiAreaQueueRedrawAll(histogram);
}
static void handlerDragBroken(uiAreaHandler *ah, uiArea *a)