/// <summary>
/// Initializes a new instance of the <see cref="AvifReader"/> class.
/// </summary>
/// <param name="parser">The parser.</param>
/// <exception cref="ArgumentNullException"><paramref name="input"/> is null.</exception>
public AvifReader(Stream input, bool leaveOpen, IByteArrayPool arrayPool)
{
if (input is null)
{
ExceptionUtil.ThrowArgumentNullException(nameof(input));
}
// The parser is initialized first because it will throw an exception
// if the AVIF file is invalid or not supported.
this.parser = new AvifParser(input, leaveOpen, arrayPool);
this.primaryItemId = this.parser.GetPrimaryItemId();
this.alphaItemId = this.parser.GetAlphaItemId(this.primaryItemId);
this.colorInfoBox = this.parser.TryGetColorInfoBox(this.primaryItemId);
this.parser.GetTransformationProperties(this.primaryItemId,
out this.cleanApertureBox,
out this.imageRotateBox,
out this.imageMirrorBox);
this.colorGridInfo = this.parser.TryGetImageGridInfo(this.primaryItemId);
if (this.alphaItemId != 0)
{
this.alphaGridInfo = this.parser.TryGetImageGridInfo(this.alphaItemId);
}
else
{
this.alphaGridInfo = null;
}
}
private void CheckImageItemType(uint itemId, ImageGridInfo gridInfo, string imageName, bool checkingGridChildren = false)
{
IItemInfoEntry entry = this.parser.TryGetItemInfoEntry(itemId);
if (entry is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image does not exist.");
}
else if (entry.ItemType != ItemInfoEntryTypes.AV01)
{
if (entry.ItemType == ItemInfoEntryTypes.ImageGrid)
{
if (checkingGridChildren)
{
ExceptionUtil.ThrowFormatException("Nested image grids are not supported.");
}
if (gridInfo is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image does not have any image grid information.");
}
IReadOnlyList <uint> childImageIds = gridInfo.ChildImageIds;
for (int i = 0; i < childImageIds.Count; i++)
{
CheckImageItemType(childImageIds[i], null, imageName, true);
}
}
else
{
ExceptionUtil.ThrowFormatException($"The { imageName } image is not a supported format.");
}
}
}
private void CheckRequiredImageProperties(uint itemId, ImageGridInfo gridInfo, string imageName)
{
bool hasUnsupportedProperties = false;
IItemInfoEntry entry = this.parser.TryGetItemInfoEntry(itemId);
if (entry is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image does not exist.");
}
else if (entry.ItemType == ItemInfoEntryTypes.AV01)
{
hasUnsupportedProperties = this.parser.HasUnsupportedEssentialProperties(itemId);
}
else if (entry.ItemType == ItemInfoEntryTypes.ImageGrid)
{
if (gridInfo is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image does not have any image grid information.");
}
IReadOnlyList <uint> childImageIds = gridInfo.ChildImageIds;
for (int i = 0; i < childImageIds.Count; i++)
{
if (this.parser.HasUnsupportedEssentialProperties(childImageIds[i]))
{
hasUnsupportedProperties = true;
break;
}
}
}
else
{
ExceptionUtil.ThrowFormatException($"The { imageName } image is not a supported format.");
}
if (hasUnsupportedProperties)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image has essential item properties that are not supported.");
}
}
private Size GetImageSize(uint itemId, ImageGridInfo gridInfo, string imageName)
{
IItemInfoEntry entry = this.parser.TryGetItemInfoEntry(itemId);
uint width;
uint height;
if (entry.ItemType == ItemInfoEntryTypes.AV01)
{
ImageSpatialExtentsBox extents = this.parser.TryGetAssociatedItemProperty <ImageSpatialExtentsBox>(itemId);
if (extents is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image size property was not found.");
}
width = extents.ImageWidth;
height = extents.ImageHeight;
}
else if (entry.ItemType == ItemInfoEntryTypes.ImageGrid)
{
if (gridInfo is null)
{
ExceptionUtil.ThrowFormatException($"The { imageName } image does not have any image grid information.");
}
width = gridInfo.OutputWidth;
height = gridInfo.OutputHeight;
}
else
{
throw new FormatException($"The { imageName } image is not a supported format.");
}
if (width > int.MaxValue || height > int.MaxValue)
{
throw new FormatException($"The { imageName } image dimensions are too large.");
}
return(new Size((int)width, (int)height));
}
private static void CheckImageGridAndTileBounds(uint tileWidth, uint tileHeight, YUVChromaSubsampling tileChroma, ImageGridInfo gridInfo)
{
// The MIAF specification (ISO/IEC 23000-22:2019) requires that the tile size be at least 64x64.
if (tileWidth < 64 || tileHeight < 64)
{
ExceptionUtil.ThrowFormatException("The image grid tile size must be at least 64x64.");
}
// HEIF (ISO/IEC 23008-12:2017), section 6.6.2.3.1:
// The tiled input images shall completely “cover” the reconstructed image grid canvas...
if ((tileWidth * gridInfo.TileColumnCount) < gridInfo.OutputWidth || (tileHeight * gridInfo.TileRowCount) < gridInfo.OutputHeight)
{
ExceptionUtil.ThrowFormatException("The image grid tiles do not cover the entire output image.");
}
if (tileChroma == YUVChromaSubsampling.Subsampling420 || tileChroma == YUVChromaSubsampling.Subsampling422)
{
if ((tileWidth & 1) != 0 || (gridInfo.OutputWidth & 1) != 0)
{
ExceptionUtil.ThrowFormatException("The tile and output image width must be an even number.");
}
if (tileChroma == YUVChromaSubsampling.Subsampling420)
{
if ((tileHeight & 1) != 0 || (gridInfo.OutputHeight & 1) != 0)
{
ExceptionUtil.ThrowFormatException("The tile and output image height must be an even number.");
}
}
}
}
