Close releases the underlying gdImagePtr. Close is idempotent. After Close, methods that read state return their documented closed-image value (Width

Width returns the image width in pixels, or 0 if the image is closed.

Height returns the image height in pixels, or 0 if the image is closed.

withReadFile invokes fn with an opened-for-read C FILE and always closes it afterwards, returning fn's error and ignoring close errors (the data, if a

withWriteFile invokes fn with an opened-for-write C FILE and propagates close errors so that buffered I/O failures (ENOSPC, EIO, ...) reach the caller

NewTrueColor creates a truecolor image.

TrueColor reports whether the image is truecolor rather than palette-based. Returns false for a closed image.

ColorsTotal returns the number of palette colors, or 0 for a closed image.

Concat returns the composition a ∘ other.

NewPalette creates a palette image with up to 256 colors.

Extract returns the bytes accumulated by a dynamic write context and consumes the context. The returned context is closed; Extract may not be called o

Has reports whether all bits in flag are present. Has(0) is always false so that callers can safely test individual constants without special-casing t

NewDynamicWriteContext creates a gdIOCtx backed by libgd-managed memory that grows as encoders write to it. Use Extract to retrieve the bytes.

String draws Latin-1 text with a built-in bitmap font.

defaultHEIFOptions fills in the structural defaults (libgd codec/chroma enums must be non-zero). Quality is left untouched: callers that pass HEIFOpti

Close releases the libgd resources backing the context. For file-backed contexts the underlying FILE is also closed and any pending I/O error is repo

NewDynamicReadContext creates a gdIOCtx that reads from a copy of data.

TransparentColor returns the transparent palette index or -1 (also for a closed image).

TrueColorAlpha composes a truecolor value using libgd channel semantics.

openFile opens path through C fopen and returns the FILE pointer along with a closer that flushes the stream and reports any deferred I/O error. The c

AffineScale returns an affine transform that scales by (scaleX, scaleY).

ClearTile detaches any tile previously registered via SetTile.

Crop returns a copy of the image cropped to rect.

DecomposeTrueColor decomposes a truecolor value.

Interlaced reports whether interlacing is enabled. Returns false for a closed image.

Resolution returns horizontal and vertical DPI, or (0, 0) for a closed image.

SetTile registers tile as the source image for libgd's tile-fill operations. libgd does not copy tile internally, so the caller must keep it alive fo

ShearHorizontal composes the receiver with a horizontal shear by angle (degrees). Returns ErrInvalidArgument if libgd rejects the shear angle (e.g. ±9

ShearVertical composes the receiver with a vertical shear by angle (degrees). Returns ErrInvalidArgument if libgd rejects the shear angle (e.g. ±90°).

String16 draws horizontal Unicode (UCS-2) text with a built-in bitmap font. An empty s is a no-op rather than an error, matching the behaviour of Stri

StringUp16 draws vertical Unicode (UCS-2) text with a built-in bitmap font.

TransformBoundingBox returns the bounding rect that contains src after applying the affine transform.

withAppendFile is the equivalent of withWriteFile but uses append mode.

AffineIdentity returns the identity affine transform.

AffineRotate returns an affine transform that rotates by angle (degrees).

AffineTranslate returns an affine transform that translates by (offsetX, offsetY).

ApplyToPoint applies the affine transform to src.

Bounds returns a rectangle covering the full image. Returns the zero Rect when the image is closed.