What Data Does Development GIMP XCF Retain?

GIMP's development-stage XCF file format is designed to store modern image attributes, non-destructive editing parameters, and high-precision graphical data that legacy versions cannot process. When working in development branches, such as GIMP 2.99.x leading toward GIMP 3.0, the XCF specification expands to maintain complex layer trees, advanced color management properties, non-destructive filter graphs, and off-canvas pixel data without rasterizing or discarding original working elements.

High Bit-Depth and Color Space Information

Development versions of XCF break away from legacy 8-bit channel limitations. When saving, the file retains:

  • Precision and Encoding: Image data stored in 16-bit integer, 32-bit integer, 16-bit floating point, or 32-bit floating point precision.
  • Color Profiles: Embedded ICC profiles and precise color space assignments (including native linear light processing and non-linear sRGB).
  • Color Models: Precision settings extending to grayscale, RGB, and CIE Lab working spaces, ensuring channel fidelity is not degraded across working sessions.

Non-Destructive Editing and GEGL Filters

A core enhancement in modern development XCF versions is the integration of GEGL (Generic Graphical Library) operations directly into the file schema:

  • Live Filters: Applied GEGL filters remain fully editable. The file saves the specific filter type, parameter values, masks, and stacking order rather than baking the effect directly into the pixel layer.
  • Non-Destructive Layer Masks and Clips: Masks, clipping sets, and link states are saved with their original mathematical definitions and references intact.

Layer and Canvas Architecture

The development-stage format preserves complex canvas dynamics that earlier stable versions either merge or discard:

  • Off-Canvas Pixels: Pixel data extending beyond the active canvas boundary is fully preserved, allowing elements to be moved back into the visible frame later without data loss.
  • Layer Sets and Grouping: Unlimited hierarchical layer nesting is supported, including pass-through blend modes and individual group mask channels.
  • Extended Blend Modes: Modern compositing formulas (such as linear burn, hard/soft light variations, and modern divide modes) are preserved via explicit algorithm identifiers.

Vector, Text, and Metadata Assets

To support non-destructive design updates, development XCF builds retain structural vector and layout assets:

  • Rich Text Metadata: Text layers keep their font family, point size, letter spacing, line height, baseline shifts, kerning, and raw markup strings.
  • Vectors and Paths: Bezier curves, anchor points, control handles, and multiple discrete path items within the project remain fully editable vector objects.
  • Standard Metadata: Embedded Exif, IPTC, and XMP metadata dictionaries are preserved alongside custom project-specific tags.

Project Environment and Utility States

The development format also serializes user workspace configurations specific to the canvas:

  • Precise guide coordinates, grid spacing, and snap-to settings.
  • Color sample points used for real-time pixel evaluation.
  • Channel visibility flags, selection boundaries, and active floating selections.