/disk1/scratch/aselle/projects/seexpr/SeExpr/src/demos/imageEditor/imageEditor.cpp

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/*
* (c) Disney Enterprises, Inc.  All rights reserved.
*
* This file is licensed under the terms of the Microsoft Public License (MS-PL)
* as defined at: http://opensource.org/licenses/MS-PL.
*
* A complete copy of this license is included in this distribution as the file
* LICENSE.
*/

#include <iostream>
#include <string>
#include <png.h>

#include <QtGui/QApplication>
#include <QtGui/QDialog>
#include <QtGui/QVBoxLayout>
#include <QtGui/QScrollArea>
#include <QtGui/QLabel>
#include <QtGui/QImage>
#include <QtGui/QPushButton>
#include <QtGui/QMessageBox>

#include <SeExprEdControlCollection.h>
#include <SeExprEditor.h>
#include <SeExprEdBrowser.h>
#include <SeExpression.h>

#include "ImageEditorDialog.h"

//-- IMAGE SYNTHESIZER CLASSES AND METHODS --//

double clamp(double x){return std::max(0.,std::min(255.,x));}

// Simple image synthesizer expression class to support demo image editor
class ImageSynthExpression:public SeExpression
{
public:
    // Constructor that takes the expression to parse
    ImageSynthExpression(const std::string& expr)
        :SeExpression(expr)
    {}

    // Simple variable that just returns its internal value
    struct Var:public SeExprScalarVarRef
    {
        Var(const double val):val(val){}
        Var(){}
        double val; // independent variable
        void eval(const SeExprVarNode* /*node*/,SeVec3d& result)
        {result[0]=val;}
    };
    // variable map
    mutable std::map<std::string,Var> vars;

    // resolve function that only supports one external variable 'x'
    SeExprVarRef* resolveVar(const std::string& name) const
    {
        std::map<std::string,Var>::iterator i=vars.find(name);
        if(i != vars.end()) return &i->second;
        return 0;
    }
};

class ImageSynthesizer
{
public:
    ImageSynthesizer();
    unsigned char *evaluateExpression(const std::string &exprStr);
private:
    int _width;
    int _height;
};

ImageSynthesizer::ImageSynthesizer()
{
    _width = 256;
    _height = 256;
}

unsigned char *ImageSynthesizer::evaluateExpression(const std::string &exprStr)
{
    ImageSynthExpression expr(exprStr);

    // make variables
    expr.vars["u"]=ImageSynthExpression::Var(0.);
    expr.vars["v"]=ImageSynthExpression::Var(0.);
    expr.vars["w"]=ImageSynthExpression::Var(_width);
    expr.vars["h"]=ImageSynthExpression::Var(_height);

    // check if expression is valid
    bool valid=expr.isValid();
    if(!valid){
        std::cerr<<"Invalid expression "<<std::endl;
        std::cerr<<expr.parseError()<<std::endl;
        return NULL;
    }

    // evaluate expression
    std::cerr<<"Evaluating expression..."<<std::endl;
    unsigned char* image=new unsigned char[_width*_height*4];
    double one_over_width=1./_width,one_over_height=1./_height;
    double& u=expr.vars["u"].val;
    double& v=expr.vars["v"].val;
    unsigned char* pixel=image;
    for(int row=0;row<_height;row++){
        for(int col=0;col<_width;col++){
            u=one_over_width*(col+.5);
            v=one_over_height*(row+.5);
            SeVec3d result=expr.evaluate();
            pixel[0]=clamp(result[2]*256.);
            pixel[1]=clamp(result[1]*256.);
            pixel[2]=clamp(result[0]*256.);
            pixel[3]=255;
            pixel+=4;
        }
    }

    return image;
}

//-- IMAGE EDITOR DIALOG METHODS --//

ImageEditorDialog::ImageEditorDialog(QWidget *parent)
    :QDialog(parent)
{
    _imageSynthesizer = new ImageSynthesizer();

    this->setWindowTitle("Image Synthesis Editor");

    // Image Previewer
    _imageLabel = new QLabel();
    _imageLabel->setFixedSize(256,256);
    _imageLabel->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter );
    QImage image("./src/doc/html/seexprlogo.png"); // just a fun default
    QPixmap imagePixmap = QPixmap::fromImage(image);
    imagePixmap = imagePixmap.scaled(256, 256, Qt::KeepAspectRatio);
    _imageLabel->setPixmap(imagePixmap);

    // Expression controls
    SeExprEdControlCollection *controls = new SeExprEdControlCollection();
    QScrollArea* scrollArea=new QScrollArea();
    scrollArea->setMinimumHeight(100);
    scrollArea->setFixedWidth(450);
    scrollArea->setWidgetResizable(true);
    scrollArea->setWidget(controls);

    // Expression editor
    _editor = new SeExprEditor(this, controls);

    // Expression browser
    SeExprEdBrowser *browser = new SeExprEdBrowser(0, _editor);

    // Set path of config.txt file containing example expressions 
    browser->setSearchPath("imageEditor", "./src/demos/imageEditor");
    browser->getExpressionDirs();
    browser->update();

    // Create apply button and connect to image preview.
    QPushButton *applyButton=new QPushButton("Apply");
    connect(applyButton, SIGNAL(clicked()), (ImageEditorDialog*)this, SLOT(applyExpression()));

    // Layout widgets: Top section contains left side with previewer and
    // controls, right side with browser.  Bottom section contains editor
    // and apply button.
    QVBoxLayout *rootLayout = new QVBoxLayout();
    this->setLayout(rootLayout);

    QWidget* topWidget=new QWidget();
    QHBoxLayout* topLayout=new QHBoxLayout();
    topLayout->setContentsMargins(0,0,0,0);
    topWidget->setLayout(topLayout);

    QWidget *leftWidget=new QWidget();
    QVBoxLayout *leftLayout=new QVBoxLayout();
    leftLayout->setContentsMargins(0,0,0,0);
    leftWidget->setLayout(leftLayout);
    leftLayout->addWidget(_imageLabel);
    leftLayout->addWidget(scrollArea,1);

    QWidget *bottomWidget=new QWidget();
    QVBoxLayout *bottomLayout=new QVBoxLayout();
    bottomLayout->setContentsMargins(0,0,0,0);
    bottomWidget->setLayout(bottomLayout);

    QWidget *buttonWidget=new QWidget();
    QHBoxLayout *buttonLayout = new QHBoxLayout(0);
    buttonWidget->setLayout(buttonLayout);
    buttonLayout->addWidget(applyButton);

    topLayout->addWidget(leftWidget);
    topLayout->addWidget(browser,1);

    bottomLayout->addWidget(_editor);
    bottomLayout->addWidget(buttonWidget);

    rootLayout->addWidget(topWidget);
    rootLayout->addWidget(bottomWidget);
}

// Apply expression, if any, from the editor contents to the preview image
void ImageEditorDialog::applyExpression()
{
    std::string exprStr = _editor->getExpr();
    if( exprStr.empty() )
    {
        QMessageBox msgBox;
        msgBox.setText("No expression entered in the editor.");
        msgBox.exec();
    } else {
        QImage image(_imageSynthesizer->evaluateExpression(exprStr),
                     256,
                     256,
                     QImage::Format_RGB32);
        if( image.isNull() )
        {
            QMessageBox msgBox;
            msgBox.setText("Error evaluating expression to create preview image.");
            msgBox.exec();
        } else {
            QPixmap imagePixmap = QPixmap::fromImage(image);
            _imageLabel->setPixmap(imagePixmap);
        }
    }
}

//-- MAIN --//

int main(int argc, char *argv[]){
    QApplication app(argc, argv);
    ImageEditorDialog *dialog = new ImageEditorDialog(0);
    dialog->show();
    app.exec();
    return 0;
}

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