Как создать гистограмму с помощью собственного метода Blackberry 10

Итак, есть эта статья на Форумы поддержки BlackBerry. Здесь есть все основы, но я так много работаю с изображениями, сгенерированными во время выполнения, что решил создать класс для их инкапсуляции. По запросу здесь представлен простой образец, основанный на одном из шаблонов Cascades. Вам также следует ознакомиться с документацией по адресу:

• http://qt-project.org/doc/qt-4.8/
• https://developer.blackberry.com/native/documentation/cascades/

И образцы файлов в BlackBerry GIT Hub.

QML-файл:

/*
 * Copyright (c) 2011-2014 BlackBerry Limited.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import bb.cascades 1.2

Page {
    Container {
        layout: DockLayout {

        }
        Label {
            // Localized text with the dynamic translation and locale updates support
            text: qsTr("Bar Graph") + Retranslate.onLocaleOrLanguageChanged
            textStyle.base: SystemDefaults.TextStyles.BigText
            horizontalAlignment: HorizontalAlignment.Center
        }
        ImageView {
            objectName: "barGraph"
            verticalAlignment: VerticalAlignment.Center
            horizontalAlignment: HorizontalAlignment.Center
        }
    }
}

Вот заголовочный файл:

 /*
 * DrawableImage.hpp
 *
 *  Created on: Jul 11, 2014
 *      Author: richard
 */

#ifndef DRAWABLEIMAGE_HPP_
#define DRAWABLEIMAGE_HPP_

#include <bb/ImageData>
#include <QtGui/QImage>
#include <bb/cascades/ImageView>

namespace net
{
    namespace test
    {

        class DrawableImage : public QImage
        {
        public:
            DrawableImage();
            DrawableImage(QSize imageSize, QImage::Format format);
            virtual ~DrawableImage();

            void    emitRenderingBegin();
            void    emitRenderingFinished();

            DrawableImage&  operator = (const QImage &image) { QImage::operator =(image); return *this; }

            QPainter        &painter();

        public:
            void    updateToView(bb::cascades::ImageView *imageView);

        private:
                void    deleteBuffer();

                QPainter        m_painter;
                QSize           m_sizeInPixels;
                unsigned char*  m_buffer; // pixel data in PixelBufferData format
        };

    } /* namespace test */
} /* namespace net */

#endif /* DRAWABLEIMAGE_HPP_ */

И файл cpp:

/*
 * DrawableImage.cpp
 *
 *  Created on: Jul 11, 2014
 *      Author: richard
 */

#include <src/DrawableImage.hpp>

namespace net
{
    namespace test
    {

        DrawableImage::DrawableImage()
            : m_painter(), m_sizeInPixels(0,0), m_buffer(NULL)
        {
            // TODO Auto-generated constructor stub

        }

        DrawableImage::DrawableImage(QSize imageSize, QImage::Format format)
            : QImage(imageSize, format), m_painter(), m_sizeInPixels(0,0), m_buffer(NULL)
        {

        }


        DrawableImage::~DrawableImage() {
            // TODO Auto-generated destructor stub
        }

        /*
        void DrawableImage::emitRenderingBegin() {
            emit renderingBegin();
        }

        void DrawableImage::emitRenderingFinished() {
            emit renderingFinished();
        }
        */

        QPainter& DrawableImage::painter() {
            if (!m_painter.isActive()) {
                m_painter.begin(this);
            }

            return m_painter;
        }

        void DrawableImage::deleteBuffer()
        {
            if (m_buffer != 0)
            {
                delete [] m_buffer;
                m_buffer = 0;
            }
        }

        void    DrawableImage::updateToView(bb::cascades::ImageView *imageView) {
            if (m_painter.isActive()) {
                m_painter.end();
            }

            Q_ASSERT(imageView != NULL);

            QImage swapped     = rgbSwapped();
            QSize  swappedSize = swapped.size();

            int w = swappedSize.width();
            int h = swappedSize.height();

            int numBytes  = w * h * 4;
            if (swappedSize != m_sizeInPixels)
            {
                deleteBuffer();
                m_sizeInPixels = QSize(w, h);
                m_buffer = new uchar[numBytes];
            }

            // Copy the memory over.
            // We'll add defensive code in case rgbSwapped has a different size
            const uchar* from = swapped.constBits();
            int numFromBytes = swapped.numBytes();
            int numToCopy = std::min(numFromBytes, numBytes);

            memcpy(m_buffer, from, numToCopy);
            if (numToCopy < numBytes)
            {
                memset(m_buffer + numToCopy, 0x00, numBytes - numToCopy);
            }

            bb::ImageData imageData = bb::ImageData::fromPixels(m_buffer, bb::PixelFormat::RGBA_Premultiplied,
                                   m_sizeInPixels.width(),
                                   m_sizeInPixels.height(),
                                   m_sizeInPixels.width() * 4);

            imageView->setImage(imageData);
        }


    } /* namespace test */
} /* namespace net */

А вот и applicationui.cpp (applicationui.hpp не изменен):

/*
 * Copyright (c) 2011-2014 BlackBerry Limited.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "applicationui.hpp"

#include <bb/cascades/Application>
#include <bb/cascades/QmlDocument>
#include <bb/cascades/AbstractPane>
#include <bb/cascades/LocaleHandler>

#include <src/DrawableImage.hpp>

using namespace bb::cascades;
using namespace net::test;

ApplicationUI::ApplicationUI() :
        QObject()
{
    // prepare the localization
    m_pTranslator = new QTranslator(this);
    m_pLocaleHandler = new LocaleHandler(this);

    bool res = QObject::connect(m_pLocaleHandler, SIGNAL(systemLanguageChanged()), this, SLOT(onSystemLanguageChanged()));
    // This is only available in Debug builds
    Q_ASSERT(res);
    // Since the variable is not used in the app, this is added to avoid a
    // compiler warning
    Q_UNUSED(res);

    // initial load
    onSystemLanguageChanged();

    // Create scene document from main.qml asset, the parent is set
    // to ensure the document gets destroyed properly at shut down.
    QmlDocument *qml = QmlDocument::create("asset:///main.qml").parent(this);

    // Create root object for the UI
    AbstractPane *root = qml->createRootObject<AbstractPane>();

    /*
     * This code exercises the DrawableImage
     */
    QSize   graphImageSize(700, 700);
    DrawableImage    graph;
    ImageView* graphImageView = root->findChild<ImageView*>("barGraph");

    // Initialise graph and fill with transparent black.
        graph = QImage(graphImageSize, QImage::Format_ARGB32_Premultiplied);
        graph.fill(Qt::black);

        // Set the background mode
        graph.painter().setBackgroundMode(Qt::TransparentMode);

        // Set rendering hints
        graph.painter().setRenderHint(QPainter::Antialiasing, true);

        for (int i = 0; i < 10; i++) {

            int x = i * (graphImageSize.width()/10);
            int h = i * (graphImageSize.height()/10) + graphImageSize.height()/20;
            int w = graphImageSize.width()/10 - 20;

            graph.painter().fillRect( x + 10, graphImageSize.height()-h, w, h, Qt::darkGreen);
        }

    // Once the image is drawn transfer it to the Cascades ImageView
    graph.updateToView(graphImageView);

    // Set created root object as the application scene
    Application::instance()->setScene(root);
}

void ApplicationUI::onSystemLanguageChanged()
{
    QCoreApplication::instance()->removeTranslator(m_pTranslator);
    // Initiate, load and install the application translation files.
    QString locale_string = QLocale().name();
    QString file_name = QString("BarGraph_%1").arg(locale_string);
    if (m_pTranslator->load(file_name, "app/native/qm")) {
        QCoreApplication::instance()->installTranslator(m_pTranslator);
    }
}

Вам также нужно будет добавить строку LIBS в файл .pro:

APP_NAME = BarGraph

CONFIG += qt warn_on cascades10
LIBS += -lbb

include(config.pri)

Вот результат: