Trait tiff::encoder::TiffKind

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pub trait TiffKind {
    type OffsetType: TryFrom<usize, Error = TryFromIntError> + Into<u64> + TiffValue;
    type OffsetArrayType: ?Sized + TiffValue;

    // Required methods
    fn write_header<W: Write>(writer: &mut TiffWriter<W>) -> TiffResult<()>;
    fn convert_offset(offset: u64) -> TiffResult<Self::OffsetType>;
    fn write_offset<W: Write>(
        writer: &mut TiffWriter<W>,
        offset: u64
    ) -> TiffResult<()>;
    fn write_entry_count<W: Write>(
        writer: &mut TiffWriter<W>,
        count: usize
    ) -> TiffResult<()>;
    fn convert_slice(slice: &[Self::OffsetType]) -> &Self::OffsetArrayType;
}
Expand description

Trait to abstract over Tiff/BigTiff differences.

Implemented for TiffKindStandard and TiffKindBig.

Required Associated Types§

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type OffsetType: TryFrom<usize, Error = TryFromIntError> + Into<u64> + TiffValue

The type of offset fields, u32 for normal Tiff, u64 for BigTiff.

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type OffsetArrayType: ?Sized + TiffValue

Needed for the convert_slice method.

Required Methods§

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fn write_header<W: Write>(writer: &mut TiffWriter<W>) -> TiffResult<()>

Write the (Big)Tiff header.

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fn convert_offset(offset: u64) -> TiffResult<Self::OffsetType>

Convert a file offset to Self::OffsetType.

This returns an error for normal Tiff if the offset is larger than u32::MAX.

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fn write_offset<W: Write>( writer: &mut TiffWriter<W>, offset: u64 ) -> TiffResult<()>

Write an offset value to the given writer.

Like convert_offset, this errors if offset > u32::MAX for normal Tiff.

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fn write_entry_count<W: Write>( writer: &mut TiffWriter<W>, count: usize ) -> TiffResult<()>

Write the IFD entry count field with the given count value.

The entry count field is an u16 for normal Tiff and u64 for BigTiff. Errors if the given usize is larger than the representable values.

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fn convert_slice(slice: &[Self::OffsetType]) -> &Self::OffsetArrayType

Internal helper method for satisfying Rust’s type checker.

The TiffValue trait is implemented for both primitive values (e.g. u8, u32) and slices of primitive values (e.g. [u8], [u32]). However, this is not represented in the type system, so there is no guarantee that that for all T: TiffValue there is also an implementation of TiffValue for [T]. This method works around that problem by providing a conversion from [T] to some value that implements TiffValue, thereby making all slices of OffsetType usable with write_tag and similar methods.

Implementations of this trait should always set OffsetArrayType to [OffsetType].

Implementors§