path: root/src/trace/potrace/inkscape-potrace.cpp

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * This is the C++ glue between Inkscape and Potrace
 *
 * Authors:
 *   Bob Jamison <rjamison@titan.com>
 *   Stéphane Gimenez <dev@gim.name>
 *
 * Copyright (C) 2004-2006 Authors
 *
 * Released under GNU GPL v2+, read the file 'COPYING' for more information.
 *
 * Potrace, the wonderful tracer located at http://potrace.sourceforge.net,
 * is provided by the generosity of Peter Selinger, to whom we are grateful.
 *
 */

#include "inkscape-potrace.h"

#include <glibmm/i18n.h>
#include <gtkmm/main.h>
#include <iomanip>

#include "trace/filterset.h"
#include "trace/quantize.h"
#include "trace/imagemap-gdk.h"

#include <inkscape.h>
#include "desktop.h"
#include "message-stack.h"

#include "object/sp-path.h"

#include <svg/path-string.h>
#include "bitmap.h"

using Glib::ustring;

static void updateGui()
{
   //## Allow the GUI to update
   Gtk::Main::iteration(false); //at least once, non-blocking
   while( Gtk::Main::events_pending() )
       Gtk::Main::iteration();

}


static void potraceStatusCallback(double /*progress*/, void *userData) /* callback fn */
{
    updateGui();

    if (!userData)
        return;

    //g_message("progress: %f\n", progress);

    //Inkscape::Trace::Potrace::PotraceTracingEngine *engine =
    //      (Inkscape::Trace::Potrace::PotraceTracingEngine *)userData;
}


namespace {
ustring twohex( int value )
{
    return ustring::format(std::hex, std::setfill(L'0'), std::setw(2), value);
}
} // namespace


//required by potrace
namespace Inkscape {

namespace Trace {

namespace Potrace {


/**
 *
 */
PotraceTracingEngine::PotraceTracingEngine() :
    keepGoing(1),
    traceType(TRACE_BRIGHTNESS),
    invert(false),
    quantizationNrColors(8),
    brightnessThreshold(0.45),
    brightnessFloor(0),
    cannyHighThreshold(0.65),
    multiScanNrColors(8),
    multiScanStack(true),
    multiScanSmooth(false),
    multiScanRemoveBackground(false)
{
    /* get default parameters */
    potraceParams = potrace_param_default();
    potraceParams->progress.callback = potraceStatusCallback;
    potraceParams->progress.data = (void *)this;
}

PotraceTracingEngine::PotraceTracingEngine(TraceType traceType, bool invert, int quantizationNrColors, double brightnessThreshold, double brightnessFloor, double cannyHighThreshold, int multiScanNrColors, bool multiScanStack, bool multiScanSmooth, bool multiScanRemoveBackground) :
  keepGoing(1), traceType(traceType), invert(invert), quantizationNrColors(quantizationNrColors), brightnessThreshold(brightnessThreshold), brightnessFloor(brightnessFloor), cannyHighThreshold(cannyHighThreshold), multiScanNrColors(multiScanNrColors) , multiScanStack(multiScanStack), multiScanSmooth(multiScanSmooth), multiScanRemoveBackground(multiScanRemoveBackground)
{
    potraceParams = potrace_param_default();
    potraceParams->progress.callback = potraceStatusCallback;
    potraceParams->progress.data = (void *)this;
}


PotraceTracingEngine::~PotraceTracingEngine()
{
    potrace_param_free(potraceParams);
}




struct Point
{
    double x;
    double y;
};


/**
 * Check a point against a list of points to see if it
 * has already occurred.
 */
static bool hasPoint(std::vector<Point> &points, double x, double y)
{
    for (auto p : points)
        {
        if (p.x == x && p.y == y)
            return true;
        }
    return false;
}


/**
 *  Recursively descend the potrace_path_t node tree, writing paths in SVG
 *  format into the output stream.  The Point vector is used to prevent
 *  redundant paths.  Returns number of paths processed.
 */
static long writePaths(PotraceTracingEngine *engine, potrace_path_t *plist,
           Inkscape::SVG::PathString& data, std::vector<Point> &points)
{
    long nodeCount = 0L;

    potrace_path_t *node;
    for (node=plist; node ; node=node->sibling)
        {
        potrace_curve_t *curve = &(node->curve);
        //g_message("node->fm:%d\n", node->fm);
        if (!curve->n)
            continue;
        const potrace_dpoint_t *pt = curve->c[curve->n - 1];
        double x0 = 0.0;
        double y0 = 0.0;
        double x1 = 0.0;
        double y1 = 0.0;
        double x2 = pt[2].x;
        double y2 = pt[2].y;
        //Have we been here already?
        if (hasPoint(points, x2, y2))
            {
            //g_message("duplicate point: (%f,%f)\n", x2, y2);
            continue;
            }
        else
            {
            Point p;
            p.x = x2; p.y = y2;
            points.push_back(p);
            }
        data.moveTo(x2, y2);
        nodeCount++;

        for (int i=0 ; i<curve->n ; i++)
            {
            if (!engine->keepGoing)
                return 0L;
            pt = curve->c[i];
            x0 = pt[0].x;
            y0 = pt[0].y;
            x1 = pt[1].x;
            y1 = pt[1].y;
            x2 = pt[2].x;
            y2 = pt[2].y;
            switch (curve->tag[i])
                {
                case POTRACE_CORNER:
                    data.lineTo(x1, y1).lineTo(x2, y2);
                break;
                case POTRACE_CURVETO:
                    data.curveTo(x0, y0, x1, y1, x2, y2);
                break;
                default:
                break;
                }
            nodeCount++;
            }
        data.closePath();

        for (potrace_path_t *child=node->childlist; child ; child=child->sibling)
            {
            nodeCount += writePaths(engine, child, data, points);
            }
        }

    return nodeCount;

}


static GrayMap *filter(PotraceTracingEngine &engine, GdkPixbuf * pixbuf)
{
    if (!pixbuf)
        return nullptr;

    GrayMap *newGm = nullptr;

    /*### Color quantization -- banding ###*/
    if (engine.traceType == TRACE_QUANT)
        {
        RgbMap *rgbmap = gdkPixbufToRgbMap(pixbuf);
        if (!rgbmap)
            return nullptr;
        //rgbMap->writePPM(rgbMap, "rgb.ppm");
        newGm = quantizeBand(rgbmap,
                            engine.quantizationNrColors);
        rgbmap->destroy(rgbmap);
        //return newGm;
        }

    /*### Brightness threshold ###*/
    else if ( engine.traceType == TRACE_BRIGHTNESS ||
              engine.traceType == TRACE_BRIGHTNESS_MULTI )
        {
        GrayMap *gm = gdkPixbufToGrayMap(pixbuf);
        if (!gm)
            return nullptr;

        newGm = GrayMapCreate(gm->width, gm->height);
        if (!newGm)
            {
            gm->destroy(gm);
            return nullptr;
            }
        double floor =  3.0 *
               ( engine.brightnessFloor * 256.0 );
        double cutoff =  3.0 *
               ( engine.brightnessThreshold * 256.0 );
        for (int y=0 ; y<gm->height ; y++)
            {
            for (int x=0 ; x<gm->width ; x++)
                {
                double brightness = (double)gm->getPixel(gm, x, y);
                if (brightness >= floor && brightness < cutoff)
                    newGm->setPixel(newGm, x, y, GRAYMAP_BLACK);  //black pixel
                else
                    newGm->setPixel(newGm, x, y, GRAYMAP_WHITE); //white pixel
                }
            }

        gm->destroy(gm);
        //newGm->writePPM(newGm, "brightness.ppm");
        //return newGm;
        }

    /*### Canny edge detection ###*/
    else if (engine.traceType == TRACE_CANNY)
        {
        GrayMap *gm = gdkPixbufToGrayMap(pixbuf);
        if (!gm)
            return nullptr;
        newGm = grayMapCanny(gm, 0.1, engine.cannyHighThreshold);
        gm->destroy(gm);
        //newGm->writePPM(newGm, "canny.ppm");
        //return newGm;
        }

    /*### Do I invert the image? ###*/
    if (newGm && engine.invert)
        {
        for (int y=0 ; y<newGm->height ; y++)
            {
            for (int x=0 ; x<newGm->width ; x++)
                {
                unsigned long brightness = newGm->getPixel(newGm, x, y);
                brightness = 765 - brightness;
                newGm->setPixel(newGm, x, y, brightness);
                }
            }
        }

    return newGm;//none of the above
}


static IndexedMap *filterIndexed(PotraceTracingEngine &engine, GdkPixbuf * pixbuf)
{
    if (!pixbuf)
        return nullptr;

    IndexedMap *newGm = nullptr;

    RgbMap *gm = gdkPixbufToRgbMap(pixbuf);
    if (!gm)
        return nullptr;
    if (engine.multiScanSmooth)
        {
        RgbMap *gaussMap = rgbMapGaussian(gm);
        newGm = rgbMapQuantize(gaussMap, engine.multiScanNrColors);
        gaussMap->destroy(gaussMap);
        }
    else
        {
        newGm = rgbMapQuantize(gm, engine.multiScanNrColors);
        }
    gm->destroy(gm);

    if (newGm && (engine.traceType == TRACE_QUANT_MONO || engine.traceType == TRACE_BRIGHTNESS_MULTI))
        {
        //Turn to grays
        for (int i=0 ; i<newGm->nrColors ; i++)
            {
            RGB rgb = newGm->clut[i];
            int grayVal = (rgb.r + rgb.g + rgb.b) / 3;
            rgb.r = rgb.g = rgb.b = grayVal;
            newGm->clut[i] = rgb;
            }
        }

    return newGm;
}




Glib::RefPtr<Gdk::Pixbuf> 
PotraceTracingEngine::preview(Glib::RefPtr<Gdk::Pixbuf> thePixbuf)
{
    GdkPixbuf *pixbuf = thePixbuf->gobj();

    if ( traceType == TRACE_QUANT_COLOR ||
         traceType == TRACE_QUANT_MONO  ||
         traceType == TRACE_BRIGHTNESS_MULTI) /* this is a lie: multipass doesn't use filterIndexed, but it's a better preview approx than filter() */
    {
        IndexedMap *gm = filterIndexed(*this, pixbuf);
        if (!gm)
            return Glib::RefPtr<Gdk::Pixbuf>(nullptr);

        Glib::RefPtr<Gdk::Pixbuf> newBuf =
             Glib::wrap(indexedMapToGdkPixbuf(gm), false);

        gm->destroy(gm);

        return newBuf;
        }
    else
        {
        GrayMap *gm = filter(*this, pixbuf);
        if (!gm)
            return Glib::RefPtr<Gdk::Pixbuf>(nullptr);

        Glib::RefPtr<Gdk::Pixbuf> newBuf =
            Glib::wrap(grayMapToGdkPixbuf(gm), false);

        gm->destroy(gm);

        return newBuf;
        }
}


//*This is the core inkscape-to-potrace binding
std::string PotraceTracingEngine::grayMapToPath(GrayMap *grayMap, long *nodeCount)
{
    if (!keepGoing)
    {
        g_warning("aborted");
        return "";
    }

    potrace_bitmap_t *potraceBitmap = bm_new(grayMap->width, grayMap->height);
    if (!potraceBitmap)
    {
        return "";
    }
    bm_clear(potraceBitmap, 0);

    //##Read the data out of the GrayMap
    for (int y=0 ; y<grayMap->height ; y++)
        {
        for (int x=0 ; x<grayMap->width ; x++)
            {
            BM_UPUT(potraceBitmap, x, y,
                  grayMap->getPixel(grayMap, x, y) ? 0 : 1);
            }
        }

    //##Debug
    /*
    FILE *f = fopen("poimage.pbm", "wb");
    bm_writepbm(f, bm);
    fclose(f);
    */

    /* trace a bitmap*/
    potrace_state_t *potraceState = potrace_trace(potraceParams,
                                                  potraceBitmap);

    //## Free the Potrace bitmap
    bm_free(potraceBitmap);

    if (!keepGoing)
        {
        g_warning("aborted");
        potrace_state_free(potraceState);
        return "";
        }

    Inkscape::SVG::PathString data;

    //## copy the path information into our d="" attribute string
    std::vector<Point> points;
    long thisNodeCount = writePaths(this, potraceState->plist, data, points);

    /* free a potrace items */
    potrace_state_free(potraceState);

    if (!keepGoing)
        return "";

    if ( nodeCount)
        *nodeCount = thisNodeCount;

    return data.string();
}



/**
 *  This is called for a single scan
 */
std::vector<TracingEngineResult> PotraceTracingEngine::traceSingle(GdkPixbuf * thePixbuf)
{

    std::vector<TracingEngineResult> results;

    if (!thePixbuf)
        return results;

    brightnessFloor = 0.0; //important to set this

    GrayMap *grayMap = filter(*this, thePixbuf);
    if (!grayMap)
        return results;

    long nodeCount = 0L;
    std::string d = grayMapToPath(grayMap, &nodeCount);

    grayMap->destroy(grayMap);

    char const *style = "fill:#000000";

    //g_message("### GOT '%s' \n", d);
    TracingEngineResult result(style, d, nodeCount);
    results.push_back(result);

    return results;
}


/**
 *  This allows routines that already generate GrayMaps to skip image filtering,
 *  increasing performance.
 */
std::vector<TracingEngineResult> PotraceTracingEngine::traceGrayMap(GrayMap *grayMap)
{

    std::vector<TracingEngineResult> results;

    brightnessFloor = 0.0; //important to set this

    long nodeCount = 0L;
    std::string d = grayMapToPath(grayMap, &nodeCount);

    char const *style = "fill:#000000";

    //g_message("### GOT '%s' \n", d);
    TracingEngineResult result(style, d, nodeCount);
    results.push_back(result);

    return results;
}

/**
 *  Called for multiple-scanning algorithms
 */
std::vector<TracingEngineResult> PotraceTracingEngine::traceBrightnessMulti(GdkPixbuf * thePixbuf)
{
    std::vector<TracingEngineResult> results;

    if ( thePixbuf ) {
        double low     = 0.2; //bottom of range
        double high    = 0.9; //top of range
        double delta   = (high - low ) / ((double)multiScanNrColors);

        brightnessFloor = 0.0; //Set bottom to black

        int traceCount = 0;

        for ( brightnessThreshold = low ;
              brightnessThreshold <= high ;
              brightnessThreshold += delta) {
            GrayMap *grayMap = filter(*this, thePixbuf);
            if ( grayMap ) {
                long nodeCount = 0L;
                std::string d = grayMapToPath(grayMap, &nodeCount);

                grayMap->destroy(grayMap);

                if ( !d.empty() ) {
                    //### get style info
                    int grayVal = (int)(256.0 * brightnessThreshold);
                    ustring style = ustring::compose("fill-opacity:1.0;fill:#%1%2%3", twohex(grayVal), twohex(grayVal), twohex(grayVal) );

                    //g_message("### GOT '%s' \n", style.c_str());
                    TracingEngineResult result(style.raw(), d, nodeCount);
                    results.push_back(result);

                    if (!multiScanStack) {
                        brightnessFloor = brightnessThreshold;
                    }

                    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
                    if (desktop) {
                        ustring msg = ustring::compose(_("Trace: %1.  %2 nodes"), traceCount++, nodeCount);
                        desktop->getMessageStack()->flash(Inkscape::NORMAL_MESSAGE, msg);
                    }
                }
            }
        }

        //# Remove the bottom-most scan, if requested
        if (results.size() > 1 && multiScanRemoveBackground) {
            results.erase(results.end() - 1);
        }
    }

    return results;
}


/**
 *  Quantization
 */
std::vector<TracingEngineResult> PotraceTracingEngine::traceQuant(GdkPixbuf * thePixbuf)
{
    std::vector<TracingEngineResult> results;

    if (thePixbuf) {
        IndexedMap *iMap = filterIndexed(*this, thePixbuf);
        if ( iMap ) {
            //Create and clear a gray map
            GrayMap *gm = GrayMapCreate(iMap->width, iMap->height);
            for (int row=0 ; row<gm->height ; row++) {
                for (int col=0 ; col<gm->width ; col++) {
                    gm->setPixel(gm, col, row, GRAYMAP_WHITE);
                }
            }

            for (int colorIndex=0 ; colorIndex<iMap->nrColors ; colorIndex++) {
                // Make a gray map for each color index
                for (int row=0 ; row<iMap->height ; row++) {
                    for (int col=0 ; col<iMap->width ; col++) {
                        int indx = (int) iMap->getPixel(iMap, col, row);
                        if (indx == colorIndex) {
                            gm->setPixel(gm, col, row, GRAYMAP_BLACK); //black
                        } else if (!multiScanStack) {
                            gm->setPixel(gm, col, row, GRAYMAP_WHITE); //white
                        }
                    }
                }

                //## Now we have a traceable graymap
                long nodeCount = 0L;
                std::string d = grayMapToPath(gm, &nodeCount);

                if ( !d.empty() ) {
                    //### get style info
                    RGB rgb = iMap->clut[colorIndex];
                    ustring style = ustring::compose("fill:#%1%2%3", twohex(rgb.r), twohex(rgb.g), twohex(rgb.b) );

                    //g_message("### GOT '%s' \n", style.c_str());
                    TracingEngineResult result(style.raw(), d, nodeCount);
                    results.push_back(result);

                    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
                    if (desktop) {
                        ustring msg = ustring::compose(_("Trace: %1.  %2 nodes"), colorIndex, nodeCount);
                        desktop->getMessageStack()->flash(Inkscape::NORMAL_MESSAGE, msg);
                    }
                }
            }// for colorIndex

            gm->destroy(gm);
            iMap->destroy(iMap);
        }

        //# Remove the bottom-most scan, if requested
        if (results.size() > 1 && multiScanRemoveBackground) {
            results.erase(results.end() - 1);
        }
    }

    return results;
}


/**
 *  This is the working method of this interface, and all
 *  implementing classes.  Take a GdkPixbuf, trace it, and
 *  return the path data that is compatible with the d="" attribute
 *  of an SVG <path> element.
 */
std::vector<TracingEngineResult>
PotraceTracingEngine::trace(Glib::RefPtr<Gdk::Pixbuf> pixbuf)
{

    GdkPixbuf *thePixbuf = pixbuf->gobj();

    //Set up for messages
    keepGoing             = 1;

    if ( traceType == TRACE_QUANT_COLOR ||
         traceType == TRACE_QUANT_MONO   )
        {
        return traceQuant(thePixbuf);
        }
    else if ( traceType == TRACE_BRIGHTNESS_MULTI )
        {
        return traceBrightnessMulti(thePixbuf);
        }
    else
        {
        return traceSingle(thePixbuf);
        }
}


/**
 *  Abort the thread that is executing getPathDataFromPixbuf()
 */
void PotraceTracingEngine::abort()
{
    //g_message("PotraceTracingEngine::abort()\n");
    keepGoing = 0;
}




}  // namespace Potrace
}  // namespace Trace
}  // namespace Inkscape

/*
  Local Variables:
  mode:c++
  c-file-style:"stroustrup"
  c-file-offsets:((innamespace . 0)(inline-open . 0))
  indent-tabs-mode:nil
  fill-column:99
  End:
*/
// vim: expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :