tools/viewer/FatBitsSlide.cpp

/*
 * Copyright 2012 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "include/core/SkBlendMode.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkFont.h"
#include "include/core/SkImageInfo.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPath.h"
#include "include/core/SkPathBuilder.h"
#include "include/core/SkPathUtils.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkShader.h"
#include "include/core/SkString.h"
#include "include/core/SkSurface.h"
#include "include/core/SkTypes.h"
#include "src/core/SkPointPriv.h"
#include "tools/ToolUtils.h"
#include "tools/fonts/FontToolUtils.h"
#include "tools/viewer/ClickHandlerSlide.h"
#include "tools/viewer/Slide.h"

#include <array>

#define FAT_PIXEL_COLOR     SK_ColorBLACK
#define PIXEL_CENTER_SIZE   3
#define WIRE_FRAME_COLOR    0xFFFF0000  /*0xFF00FFFF*/
#define WIRE_FRAME_SIZE     1.5f

static SkScalar apply_grid(SkScalar x) {
    const SkScalar grid = 2;
    return SkScalarRoundToScalar(x * grid) / grid;
}

static void apply_grid(SkPoint pts[], int count) {
    for (int i = 0; i < count; ++i) {
        pts[i].set(apply_grid(pts[i].fX), apply_grid(pts[i].fY));
    }
}

static void erase(SkSurface* surface) {
    surface->getCanvas()->clear(SK_ColorTRANSPARENT);
}

class FatBits {
public:
    FatBits() {
        fAA = false;
        fStyle = kHair_Style;
        fGrid = false;
        fShowSkeleton = true;
        fUseClip = false;
        fRectAsOval = false;
        fUseTriangle = false;
        fStrokeCap = SkPaint::kButt_Cap;

        fClipRect.setLTRB(2, 2, 11, 8);
    }

    int getZoom() const { return fZoom; }

    bool getAA() const { return fAA; }
    void setAA(bool aa) { fAA = aa; }

    bool getGrid() const { return fGrid; }
    void setGrid(bool g) { fGrid = g; }

    bool getShowSkeleton() const { return fShowSkeleton; }
    void setShowSkeleton(bool ss) { fShowSkeleton = ss; }

    bool getTriangle() const { return fUseTriangle; }
    void setTriangle(bool ut) { fUseTriangle = ut; }

    void toggleRectAsOval() { fRectAsOval = !fRectAsOval; }

    void togglePixelColors() {
        if (fShader == fShader0) {
            fShader = fShader1;
        } else {
            fShader = fShader0;
        }
    }

    float fStrokeWidth = 1;

    bool getUseClip() const { return fUseClip; }
    void setUseClip(bool uc) { fUseClip = uc; }

    enum Style {
        kHair_Style,
        kStroke_Style,
    };
    Style getStyle() const { return fStyle; }
    void setStyle(Style s) { fStyle = s; }

    void setWHZ(int width, int height, int zoom) {
        fW = width;
        fH = height;
        fZoom = zoom;
        fBounds.setIWH(width * zoom, height * zoom);
        fMatrix.setScale(SkIntToScalar(zoom), SkIntToScalar(zoom));
        fInverse.setScale(SK_Scalar1 / zoom, SK_Scalar1 / zoom);
        fShader0 = ToolUtils::create_checkerboard_shader(0xFFDDDDDD, 0xFFFFFFFF, zoom);
        fShader1 = SkShaders::Color(SK_ColorWHITE);
        fShader = fShader0;

        SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
        fMinSurface = SkSurfaces::Raster(info);
        info = info.makeWH(width * zoom, height * zoom);
        fMaxSurface = SkSurfaces::Raster(info);
    }

    void drawBG(SkCanvas*);
    void drawFG(SkCanvas*);
    void drawLine(SkCanvas*, SkPoint pts[2]);
    void drawRect(SkCanvas* canvas, SkPoint pts[2]);
    void drawTriangle(SkCanvas* canvas, SkPoint pts[3]);

    SkPaint::Cap fStrokeCap;

private:
    bool fAA, fGrid, fShowSkeleton, fUseClip, fRectAsOval, fUseTriangle;
    Style fStyle;
    int fW, fH, fZoom;
    SkMatrix            fMatrix, fInverse;
    SkRect              fBounds, fClipRect;
    sk_sp<SkShader>     fShader0;
    sk_sp<SkShader>     fShader1;
    sk_sp<SkShader>     fShader;
    sk_sp<SkSurface>    fMinSurface;
    sk_sp<SkSurface>    fMaxSurface;

    void setupPaint(SkPaint* paint) {
        bool aa = this->getAA();
        paint->setStrokeCap(fStrokeCap);
        switch (fStyle) {
            case kHair_Style:
                paint->setStrokeWidth(0);
                break;
            case kStroke_Style:
                paint->setStrokeWidth(fStrokeWidth);
                break;
        }
        paint->setAntiAlias(aa);
    }

    void setupSkeletonPaint(SkPaint* paint) {
        paint->setStyle(SkPaint::kStroke_Style);
        paint->setStrokeWidth(WIRE_FRAME_SIZE);
        paint->setColor(fShowSkeleton ? WIRE_FRAME_COLOR : 0);
        paint->setAntiAlias(true);
    }

    void drawTriangleSkeleton(SkCanvas* max, const SkPoint pts[]);
    void drawLineSkeleton(SkCanvas* max, const SkPoint pts[]);
    void drawRectSkeleton(SkCanvas* max, const SkRect& r) {
        SkPaint paint;
        this->setupSkeletonPaint(&paint);
        SkPath path = fRectAsOval ? SkPath::Oval(r) : SkPath::Rect(r);
        max->drawPath(path, paint);
    }

    void copyMinToMax() {
        erase(fMaxSurface.get());
        SkCanvas* canvas = fMaxSurface->getCanvas();
        canvas->save();
        canvas->concat(fMatrix);
        fMinSurface->draw(canvas, 0, 0);
        canvas->restore();

        SkPaint paint;
        paint.setBlendMode(SkBlendMode::kClear);
        for (int iy = 1; iy < fH; ++iy) {
            SkScalar y = SkIntToScalar(iy * fZoom);
            canvas->drawLine(0, y - SK_ScalarHalf, 999, y - SK_ScalarHalf, paint);
        }
        for (int ix = 1; ix < fW; ++ix) {
            SkScalar x = SkIntToScalar(ix * fZoom);
            canvas->drawLine(x - SK_ScalarHalf, 0, x - SK_ScalarHalf, 999, paint);
        }
    }
};

void FatBits::drawBG(SkCanvas* canvas) {
    SkPaint paint;

    paint.setShader(fShader);
    canvas->drawRect(fBounds, paint);
    paint.setShader(nullptr);
}

void FatBits::drawFG(SkCanvas* canvas) {
    SkPaint inner, outer;

    inner.setAntiAlias(true);
    inner.setColor(SK_ColorBLACK);
    inner.setStrokeWidth(PIXEL_CENTER_SIZE);

    outer.setAntiAlias(true);
    outer.setColor(SK_ColorWHITE);
    outer.setStrokeWidth(PIXEL_CENTER_SIZE + 2);

    SkScalar half = SkIntToScalar(fZoom) / 2;
    for (int iy = 0; iy < fH; ++iy) {
        SkScalar y = SkIntToScalar(iy * fZoom) + half;
        for (int ix = 0; ix < fW; ++ix) {
            SkScalar x = SkIntToScalar(ix * fZoom) + half;

            canvas->drawPoint(x, y, outer);
            canvas->drawPoint(x, y, inner);
        }
    }

    if (fUseClip) {
        SkPaint p;
        p.setStyle(SkPaint::kStroke_Style);
        p.setColor(SK_ColorLTGRAY);
        SkRect r = {
            fClipRect.fLeft * fZoom,
            fClipRect.fTop * fZoom,
            fClipRect.fRight * fZoom,
            fClipRect.fBottom * fZoom
        };
        canvas->drawRect(r, p);
    }
}

void FatBits::drawLineSkeleton(SkCanvas* max, const SkPoint pts[]) {
    SkPaint paint;
    this->setupSkeletonPaint(&paint);

    SkPath path = SkPath::Line(pts[0], pts[1]);

    if (fStyle == kStroke_Style) {
        SkPaint p;
        p.setStyle(SkPaint::kStroke_Style);
        p.setStrokeWidth(fStrokeWidth * fZoom);
        p.setStrokeCap(fStrokeCap);
        SkPathBuilder dst;
        skpathutils::FillPathWithPaint(path, p, &dst);
        dst.moveTo(pts[0]);
        dst.lineTo(pts[1]);
        path = dst.detach();
    }
    max->drawPath(path, paint);
}

void FatBits::drawLine(SkCanvas* canvas, SkPoint pts[2]) {
    SkPaint paint;

    fInverse.mapPoints({pts, 2});

    if (fGrid) {
        apply_grid(pts, 2);
    }

    erase(fMinSurface.get());
    this->setupPaint(&paint);
    paint.setColor(FAT_PIXEL_COLOR);
    if (fUseClip) {
        fMinSurface->getCanvas()->save();
        SkRect r = fClipRect;
        r.inset(SK_Scalar1/3, SK_Scalar1/3);
        fMinSurface->getCanvas()->clipRect(r, SkClipOp::kIntersect, true);
    }
    fMinSurface->getCanvas()->drawLine(pts[0], pts[1], paint);
    if (fUseClip) {
        fMinSurface->getCanvas()->restore();
    }
    this->copyMinToMax();

    SkCanvas* max = fMaxSurface->getCanvas();

    fMatrix.mapPoints({pts, 2});
    this->drawLineSkeleton(max, pts);

    fMaxSurface->draw(canvas, 0, 0);
}

void FatBits::drawRect(SkCanvas* canvas, SkPoint pts[2]) {
    SkPaint paint;

    fInverse.mapPoints({pts, 2});

    if (fGrid) {
        apply_grid(pts, 2);
    }

    SkRect r = SkRect::BoundsOrEmpty({pts, 2});

    erase(fMinSurface.get());
    this->setupPaint(&paint);
    paint.setColor(FAT_PIXEL_COLOR);
    {
        SkCanvas* c = fMinSurface->getCanvas();
        fRectAsOval ? c->drawOval(r, paint) : c->drawRect(r, paint);
    }
    this->copyMinToMax();

    SkCanvas* max = fMaxSurface->getCanvas();

    fMatrix.mapPoints({pts, 2});
    r = SkRect::BoundsOrEmpty({pts, 2});
    this->drawRectSkeleton(max, r);

    fMaxSurface->draw(canvas, 0, 0);
}

void FatBits::drawTriangleSkeleton(SkCanvas* max, const SkPoint pts[]) {
    SkPaint paint;
    this->setupSkeletonPaint(&paint);

    SkPath path = SkPath::Polygon({pts, 3}, true);

    max->drawPath(path, paint);
}

void FatBits::drawTriangle(SkCanvas* canvas, SkPoint pts[3]) {
    SkPaint paint;

    fInverse.mapPoints({pts, 3});

    if (fGrid) {
        apply_grid(pts, 3);
    }

    SkPath path = SkPath::Polygon({pts, 3}, true);

    erase(fMinSurface.get());
    this->setupPaint(&paint);
    paint.setColor(FAT_PIXEL_COLOR);
    fMinSurface->getCanvas()->drawPath(path, paint);
    this->copyMinToMax();

    SkCanvas* max = fMaxSurface->getCanvas();

    fMatrix.mapPoints({pts, 3});
    this->drawTriangleSkeleton(max, pts);

    fMaxSurface->draw(canvas, 0, 0);
}

///////////////////////////////////////////////////////////////////////////////////////////////////

class IndexClick : public ClickHandlerSlide::Click {
    int fIndex;

public:
    IndexClick(int index) : fIndex(index) {}

    static int GetIndex(Click* click) { return ((IndexClick*)click)->fIndex; }
};

class DrawLineSlide : public ClickHandlerSlide {
    FatBits fFB;
    SkPoint fPts[3];
    bool    fIsRect;
    int     fZoom = 64;

public:
    DrawLineSlide() {
        fFB.setWHZ(24*2, 16*2, fZoom);
        fPts[0].set(1, 1);
        fPts[1].set(5, 4);
        fPts[2].set(2, 6);
        SkMatrix::Scale(fZoom, fZoom).mapPoints(fPts);
        fIsRect = false;
        fName = "FatBits";
    }

    void setStyle(FatBits::Style s) { fFB.setStyle(s); }

    bool onChar(SkUnichar uni) override {
        switch (uni) {
            case 'c':
                fFB.setUseClip(!fFB.getUseClip());
                return true;
            case 'r':
                fIsRect = !fIsRect;
                return true;
            case 'o':
                fFB.toggleRectAsOval();
                return true;
            case 'x':
                fFB.setGrid(!fFB.getGrid());
                return true;
            case 's':
                if (FatBits::kStroke_Style == fFB.getStyle()) {
                    this->setStyle(FatBits::kHair_Style);
                } else {
                    this->setStyle(FatBits::kStroke_Style);
                }
                return true;
            case 'k': {
                const auto caps = std::to_array<SkPaint::Cap>({
                        SkPaint::kButt_Cap,
                        SkPaint::kRound_Cap,
                        SkPaint::kSquare_Cap,
                });
                fFB.fStrokeCap = caps[(fFB.fStrokeCap + 1) % 3];
                return true;
            }
            case 'a':
                fFB.setAA(!fFB.getAA());
                return true;
            case 'w':
                fFB.setShowSkeleton(!fFB.getShowSkeleton());
                return true;
            case 'g':
                fFB.togglePixelColors();
                return true;
            case 't':
                fFB.setTriangle(!fFB.getTriangle());
                return true;
            case '-':
                fFB.fStrokeWidth -= 0.125f;
                return true;
            case '=':
                fFB.fStrokeWidth += 0.125f;
                return true;
        }
        return false;
    }

    void draw(SkCanvas* canvas) override {
        fFB.drawBG(canvas);
        if (fFB.getTriangle()) {
            fFB.drawTriangle(canvas, fPts);
        } else if (fIsRect) {
            fFB.drawRect(canvas, fPts);
        } else {
            fFB.drawLine(canvas, fPts);
        }
        fFB.drawFG(canvas);

        {
            SkString str;
            str.printf("%s %s %s",
                       fFB.getAA() ? "AA" : "BW",
                       FatBits::kHair_Style == fFB.getStyle() ? "Hair" : "Stroke",
                       fFB.getUseClip() ? "clip" : "noclip");
            SkPaint paint;
            paint.setColor(SK_ColorBLUE);
            SkFont font(ToolUtils::DefaultTypeface(), 16);
            canvas->drawString(str, 10, 16, font, paint);
        }
    }

protected:
    Click* onFindClickHandler(SkScalar x, SkScalar y, skui::ModifierKey modi) override {
        SkPoint pt = { x, y };
        int index = -1;
        int count = fFB.getTriangle() ? 3 : 2;
        SkScalar tol = 12;

        for (int i = 0; i < count; ++i) {
            if (SkPointPriv::EqualsWithinTolerance(fPts[i], pt, tol)) {
                index = i;
                break;
            }
        }
        return new IndexClick(index);
    }

    bool onClick(Click* click) override {
        int index = IndexClick::GetIndex(click);
        if (index >= 0 && index <= 2) {
            fPts[index] = click->fCurr;
        } else {
            SkScalar dx = click->fCurr.fX - click->fPrev.fX;
            SkScalar dy = click->fCurr.fY - click->fPrev.fY;
            fPts[0].offset(dx, dy);
            fPts[1].offset(dx, dy);
            fPts[2].offset(dx, dy);
        }
        return true;
    }
};

//////////////////////////////////////////////////////////////////////////////

DEF_SLIDE(return new DrawLineSlide();)