CODEWITHSUNDEEP
c#imagerotation
user1763295
user1763295

Reputation: 1088

Image RotateFlip only working when called directly

I have a class for my sprites like so:

public class Sprite : System.ICloneable
{
    public Image SpriteImage { get; private set; }
    public Image SpriteMask { get; private set; }

    public Sprite(Image img, Image maskImg = null)
    {
        this.SetImage(img, maskImg);
    }

    public void SetImage(Image img, Image maskImg = null)
    {
        this.SpriteImage = new Bitmap(img,img.Width,img.Height);

        if (maskImg != null)
        {
            this.SpriteMask = new Bitmap(maskImg, maskImg.Width, maskImg.Height);
        }
        else
        {
            this.SpriteMask = this.SpriteImage;
        }
    }

    public virtual object Clone()
    {
        return new Sprite(this.SpriteImage,this.SpriteMask);
    }

    public void FlipHorizontally()
    {
        this.SpriteImage.RotateFlip(RotateFlipType.RotateNoneFlipX);
        this.SpriteMask.RotateFlip(RotateFlipType.RotateNoneFlipX);
    }

    public void FlipVertically()
    {
        this.SpriteImage.RotateFlip(RotateFlipType.RotateNoneFlipY);
        this.SpriteMask.RotateFlip(RotateFlipType.RotateNoneFlipY);
    }
}

since I have SpriteMask and SpriteImage I created a function to rotate them both without hassle. In another class I have:

public void ChangeDirection(bool facingRight)
{
    if (facingRight != this.FacingRight)
    {

        for(int i = 0; i < this.Sprites.Count; i++)
        {
            this.Sprites[i].FlipHorizontally();
        }

        foreach (Weapon weapon in this.CollectedWeapons)
        {
            weapon.ChangeDirection(facingRight);
        }
        this.FacingRight = facingRight;
    }
}

this.Sprites is List<Sprite> Sprites;. Now when this code is ran, the sprites to not flip, but if I change sprite.FlipHorizontally to this.Sprites[i].SpriteImage.RotateFlip(RotateFlipType.RotateNoneFlipX); it works fine. Why is this?

Upvotes: 2

Views: 1018

Answers (1)

J...
J...

Reputation: 31393

In your Sprite constructor you allow the sprite mask argument to be null. If it is null, look at what you do :

if (maskImg != null)
{
    this.SpriteMask = new Bitmap(maskImg, maskImg.Width, maskImg.Height);
}
else
{
    this.SpriteMask = this.SpriteImage;
}

You set SpriteMask to SpriteImage - since an image is a reference type you are only assigning the reference. There is still only one Image object but both variables are pointing to it. When you call : 

public void FlipHorizontally()
{
    this.SpriteImage.RotateFlip(RotateFlipType.RotateNoneFlipX);
    this.SpriteMask.RotateFlip(RotateFlipType.RotateNoneFlipX);
}

...since SpriteImage and SpriteMask are the same object, you are flipping the image and then flipping it back again. What you might consider is making a copy of the sprite image for the mask if the mask is not provided :

if (maskImg != null)
{
    this.SpriteMask = new Bitmap(maskImg, maskImg.Width, maskImg.Height);
}
else
{
    this.SpriteMask = new Bitmap(this.SpriteImage);
}

Upvotes: 1

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