canvaswidget.cpp - mozsearch

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// Copyright (C) 2025 The Qt Company Ltd.

// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

#include "canvaswidget.h"

#include <QCanvasPainter>

#include <QCanvasRadialGradient>

#include <QCanvasImagePattern>

using namespace Qt::StringLiterals;

CanvasWidget::CanvasWidget()

    setFillColor(Qt::white);

//![image]

void CanvasWidget::initializeResources(QCanvasPainter *p)

    Q_ASSERT(m_image.isNull());

    const auto flags = QCanvasPainter::ImageFlag::Repeat | QCanvasPainter::ImageFlag::GenerateMipmaps;

    m_image = p->addImage(QImage(u":/qt-translucent.png"_s), flags);

void CanvasWidget::graphicsResourcesInvalidated()

    m_image = {};

//![image]

//![paint]

void CanvasWidget::paint(QCanvasPainter *p)

    const float size = std::min(width(), height());

    const float centerX = width() / 2;

    const float centerY = height() / 2;

    // Paint the background circle

    QCanvasRadialGradient gradient1(centerX, centerY - size * 0.1f, 0, size * 0.6f);

    gradient1.setStartColor(QColor(0x909090));

    gradient1.setEndColor(QColor(0x404040));

    p->beginPath();

    p->circle(QPointF(centerX, centerY), size * 0.46f);

    p->setFillStyle(gradient1);

    p->fill();

    p->setStrokeStyle(QColor(0x202020));

    p->setLineWidth(size * 0.02f);

    p->stroke();

//![paint]

    // Hello text

    p->setTextAlign(QCanvasPainter::TextAlign::Center);

    p->setTextBaseline(QCanvasPainter::TextBaseline::Middle);

    QFont font1;

    font1.setWeight(QFont::Weight::Bold);

    font1.setItalic(true);

    font1.setPixelSize(qRound(size * 0.08f));

    p->setFont(font1);

    p->setFillStyle(QColor(0xB0D040));

    p->fillText(u"HELLO"_s, centerX, centerY - size * 0.18f);

    // QCanvasPainter text

    QFont font2;

    font2.setWeight(QFont::Weight::Thin);

    font2.setPixelSize(qRound(size * 0.11f));

    p->setFont(font2);

    p->fillText(u"Qt Canvas Painter"_s, centerX, centerY - size * 0.08f);

//![pattern]

    // Paint heart

    QCanvasImagePattern pattern(m_image, centerX, centerY, size * 0.08f, size * 0.05f);

    p->setFillStyle(pattern);

//![pattern]

    p->setLineCap(QCanvasPainter::LineCap::Round);

    p->setStrokeStyle(QColor(0xB0D040));

    p->beginPath();

    p->moveTo(centerX, centerY + size * 0.3f);

    p->bezierCurveTo(centerX - size * 0.25f, centerY + size * 0.1f,

                     centerX - size * 0.05f, centerY + size * 0.05f,

                     centerX, centerY + size * 0.15f);

    p->bezierCurveTo(centerX + size * 0.05f, centerY + size * 0.05f,

                     centerX + size * 0.25f, centerY + size * 0.1f,

                     centerX, centerY + size * 0.3f);

    p->stroke();

    p->fill();