source/modules/juce_graphics/images/juce_ScaledImage.h

   1 /*
   2   ==============================================================================
   3
   4    This file is part of the JUCE library.
   5    Copyright (c) 2022 - Raw Material Software Limited
   6
   7    JUCE is an open source library subject to commercial or open-source
   8    licensing.
   9
  10    By using JUCE, you agree to the terms of both the JUCE 7 End-User License
  11    Agreement and JUCE Privacy Policy.
  12
  13    End User License Agreement: www.juce.com/juce-7-licence
  14    Privacy Policy: www.juce.com/juce-privacy-policy
  15
  16    Or: You may also use this code under the terms of the GPL v3 (see
  17    www.gnu.org/licenses).
  18
  19    JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
  20    EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
  21    DISCLAIMED.
  22
  23   ==============================================================================
  24 */
  25
  26 namespace juce
  27 {
  28
  29 /**
  30     An image that will be resampled before it is drawn.
  31
  32     A plain Image only stores plain pixels, but does not store any information
  33     about how these pixels correspond to points. This means that if the image's
  34     dimensions are interpreted as points, then the image will be blurry when
  35     drawn on high resolution displays. If the image's dimensions are instead
  36     interpreted as corresponding to exact pixel positions, then the logical
  37     size of the image will change depending on the scale factor of the screen
  38     used to draw it.
  39
  40     The ScaledImage class is designed to store an image alongside a scale
  41     factor that informs a renderer how to convert between the image's pixels
  42     and points.
  43 */
  44 class JUCE_API  ScaledImage
  45 {
  46 public:
  47     /** Creates a ScaledImage with an invalid image and unity scale.
  48     */
  49     ScaledImage() = default;
  50
  51     /** Creates a ScaledImage from an Image, where the dimensions of the image
  52         in pixels are exactly equal to its dimensions in points.
  53     */
  54     explicit ScaledImage (const Image& imageIn)
  55         : ScaledImage (imageIn, 1.0) {}
  56
  57     /** Creates a ScaledImage from an Image, using a custom scale factor.
  58
  59         A scale of 1.0 means that the image's dimensions in pixels is equal to
  60         its dimensions in points.
  61
  62         A scale of 2.0 means that the image contains 2 pixels per point in each
  63         direction.
  64     */
  65     ScaledImage (const Image& imageIn, double scaleIn)
  66         : image (imageIn), scaleFactor (scaleIn) {}
  67
  68     /** Returns the image at its original dimensions. */
  69     Image getImage() const { return image; }
  70
  71     /** Returns the image's scale. */
  72     double getScale() const { return scaleFactor; }
  73
  74     /** Returns the bounds of this image expressed in points. */
  75     Rectangle<double> getScaledBounds() const { return image.getBounds().toDouble() / scaleFactor; }
  76
  77 private:
  78     Image image;
  79     double scaleFactor = 1.0;
  80 };
  81
  82 } // namespace juce