ChartSlide.cpp File Reference

#include "include/core/SkCanvas.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPathBuilder.h"
#include "include/private/base/SkTDArray.h"
#include "src/base/SkRandom.h"
#include "tools/viewer/Slide.h"

Go to the source code of this file.

Classes
class	ChartSlide

Functions
static void	gen_data (SkScalar yAvg, SkScalar ySpread, int count, SkTDArray< SkScalar > *dataPts)
static void	gen_paths (const SkTDArray< SkScalar > &topData, const SkTDArray< SkScalar > *bottomData, SkScalar yBase, SkScalar xLeft, SkScalar xDelta, int leftShift, SkPathBuilder *plot, SkPathBuilder *fill)

Function Documentation

gen_data()

static void gen_data ( SkScalar  yAvg, SkScalar  ySpread, int  count, SkTDArray< SkScalar > *  dataPts  )

static

Definition at line 16 of file ChartSlide.cpp.

                                                                                               {
    dataPts->resize(count);
    static SkRandom gRandom;
    for (int i = 0; i < count; ++i) {
        (*dataPts)[i] = gRandom.nextRangeScalar(yAvg - SkScalarHalf(ySpread),
                                                yAvg + SkScalarHalf(ySpread));
    }
}

gen_paths()

static void gen_paths ( const SkTDArray< SkScalar > &  topData, const SkTDArray< SkScalar > *  bottomData, SkScalar  yBase, SkScalar  xLeft, SkScalar  xDelta, int  leftShift, SkPathBuilder *  plot, SkPathBuilder *  fill  )

static

Definition at line 29 of file ChartSlide.cpp.

                                                                {
    plot->incReserve(topData.size());
    if (nullptr == bottomData) {
        fill->incReserve(topData.size() + 2);
    } else {
        fill->incReserve(2 * topData.size());
    }
 
    leftShift %= topData.size();
    SkScalar x = xLeft;
 
    // Account for the leftShift using two loops
    int shiftToEndCount = topData.size() - leftShift;
    plot->moveTo(x, topData[leftShift]);
    fill->moveTo(x, topData[leftShift]);
 
    for (int i = 1; i < shiftToEndCount; ++i) {
        plot->lineTo(x, topData[i + leftShift]);
        fill->lineTo(x, topData[i + leftShift]);
        x += xDelta;
    }
 
    for (int i = 0; i < leftShift; ++i) {
        plot->lineTo(x, topData[i]);
        fill->lineTo(x, topData[i]);
        x += xDelta;
    }
 
    if (bottomData) {
        SkASSERT(bottomData->size() == topData.size());
        // iterate backwards over the previous graph's data to generate the bottom of the filled
        // area (and account for leftShift).
        for (int i = 0; i < leftShift; ++i) {
            x -= xDelta;
            fill->lineTo(x, (*bottomData)[leftShift - 1 - i]);
        }
        for (int i = 0; i < shiftToEndCount; ++i) {
            x -= xDelta;
            fill->lineTo(x, (*bottomData)[bottomData->size() - 1 - i]);
        }
    } else {
        fill->lineTo(x - xDelta, yBase);
        fill->lineTo(xLeft, yBase);
    }
}