JUCE/modules/juce_gui_basics/buttons/juce_ImageButton.cpp

/*
  ==============================================================================

   This file is part of the JUCE 7 technical preview.
   Copyright (c) 2022 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For the technical preview this file cannot be licensed commercially.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

ImageButton::ImageButton (const String& text_)
    : Button (text_),
      scaleImageToFit (true),
      preserveProportions (true),
      alphaThreshold (0)
{
}

ImageButton::~ImageButton()
{
}

void ImageButton::setImages (const bool resizeButtonNowToFitThisImage,
                             const bool rescaleImagesWhenButtonSizeChanges,
                             const bool preserveImageProportions,
                             const Image& normalImage_,
                             const float imageOpacityWhenNormal,
                             Colour overlayColourWhenNormal,
                             const Image& overImage_,
                             const float imageOpacityWhenOver,
                             Colour overlayColourWhenOver,
                             const Image& downImage_,
                             const float imageOpacityWhenDown,
                             Colour overlayColourWhenDown,
                             const float hitTestAlphaThreshold)
{
    normalImage = normalImage_;
    overImage = overImage_;
    downImage = downImage_;

    if (resizeButtonNowToFitThisImage && normalImage.isValid())
    {
        imageBounds.setSize (normalImage.getWidth(),
                             normalImage.getHeight());

        setSize (imageBounds.getWidth(), imageBounds.getHeight());
    }

    scaleImageToFit = rescaleImagesWhenButtonSizeChanges;
    preserveProportions = preserveImageProportions;

    normalOpacity = imageOpacityWhenNormal;
    normalOverlay = overlayColourWhenNormal;
    overOpacity   = imageOpacityWhenOver;
    overOverlay   = overlayColourWhenOver;
    downOpacity   = imageOpacityWhenDown;
    downOverlay   = overlayColourWhenDown;

    alphaThreshold = (uint8) jlimit (0, 0xff, roundToInt (255.0f * hitTestAlphaThreshold));

    repaint();
}

Image ImageButton::getCurrentImage() const
{
    if (isDown() || getToggleState())
        return getDownImage();

    if (isOver())
        return getOverImage();

    return getNormalImage();
}

Image ImageButton::getNormalImage() const
{
    return normalImage;
}

Image ImageButton::getOverImage() const
{
    return overImage.isValid() ? overImage
                               : normalImage;
}

Image ImageButton::getDownImage() const
{
    return downImage.isValid() ? downImage
                               : getOverImage();
}

void ImageButton::paintButton (Graphics& g,
                               bool shouldDrawButtonAsHighlighted,
                               bool shouldDrawButtonAsDown)
{
    if (! isEnabled())
    {
        shouldDrawButtonAsHighlighted = false;
        shouldDrawButtonAsDown = false;
    }

    Image im (getCurrentImage());

    if (im.isValid())
    {
        const int iw = im.getWidth();
        const int ih = im.getHeight();
        int w = getWidth();
        int h = getHeight();
        int x = (w - iw) / 2;
        int y = (h - ih) / 2;

        if (scaleImageToFit)
        {
            if (preserveProportions)
            {
                int newW, newH;
                const float imRatio = (float) ih / (float) iw;
                const float destRatio = (float) h / (float) w;

                if (imRatio > destRatio)
                {
                    newW = roundToInt ((float) h / imRatio);
                    newH = h;
                }
                else
                {
                    newW = w;
                    newH = roundToInt ((float) w * imRatio);
                }

                x = (w - newW) / 2;
                y = (h - newH) / 2;
                w = newW;
                h = newH;
            }
            else
            {
                x = 0;
                y = 0;
            }
        }

        if (! scaleImageToFit)
        {
            w = iw;
            h = ih;
        }

        imageBounds.setBounds (x, y, w, h);

        const bool useDownImage = shouldDrawButtonAsDown || getToggleState();

        getLookAndFeel().drawImageButton (g, &im, x, y, w, h,
                                          useDownImage ? downOverlay
                                                       : (shouldDrawButtonAsHighlighted ? overOverlay
                                                                            : normalOverlay),
                                          useDownImage ? downOpacity
                                                       : (shouldDrawButtonAsHighlighted ? overOpacity
                                                                            : normalOpacity),
                                          *this);
    }
}

bool ImageButton::hitTest (int x, int y)
{
    if (! Component::hitTest (x, y)) // handle setInterceptsMouseClicks
        return false;

    if (alphaThreshold == 0)
        return true;

    Image im (getCurrentImage());

    return im.isNull() || ((! imageBounds.isEmpty())
                            && alphaThreshold < im.getPixelAt (((x - imageBounds.getX()) * im.getWidth()) / imageBounds.getWidth(),
                                                               ((y - imageBounds.getY()) * im.getHeight()) / imageBounds.getHeight()).getAlpha());
}

} // namespace juce