Abstract: Examples include computing devices, processes, and/or machine-readable storage mediums. Examples analyze a region of pixels for a digital image to determine a set of diagonal direction pixel differences corresponding to a target pixel. Examples analyze the region of pixels to determine diagonal variances corresponding to the target pixel. Examples scale the digital image by processing the target pixel into a set of subpixels based at least in part on the set of diagonal direction pixel differences and the diagonal variances.

Abstract: A system includes a memory to store ink-channel data that describe print resources for an ink-channel printing pipeline and Neugebauer Primary area coverage (NPac) data of an alternative printing pipeline. An NPac property stored in the memory describes a dimensional relationship between the NPac data of the alternative printing pipeline and the ink-channel data for the ink-channel printing pipeline. The system includes a processor to execute instructions stored in the memory. The instructions generate a mapping file based on the NPac property to map from an ink-channel space described by the ink-channel data to an NPac space described by the NPac data.

Abstract: Methods and apparatus relating to substructures for 3D objects are described. In an example, a method for providing a three-dimensional halftone threshold matrix is described. The method may comprise receiving a substructure model representing a three-dimensional material structure and populating each location in the substructure model at which the structure exists with a halftone threshold value.

Abstract: Certain examples described herein relate to a three-dimensional threshold matrix. The three-dimensional threshold matrix may be used for three-dimensional halftoning. In one example, values for a predefined two-dimensional threshold matrix are shifted with respect to a third dimension to provide the three-dimensional threshold matrix. In one example, the three-dimensional threshold matrix may then be processed in association with a digital representation of a three-dimensional object to output discrete material arrangement instructions for at least one production material. The instructions may be used to control an additive manufacturing system to produce the three-dimensional object.

Abstract: A memory device includes a compressed color table and corrective information. The compressed color table includes a first set of nodes of the color table compressed with a lossy compression at a selected compression ratio. The first set of nodes include a color difference within an error threshold at the selected compression ratio. Corrective information is included for a second set of nodes of the color table. The second set of nodes have a color difference outside the error threshold.

Abstract: Color data may be collected from a plurality of sources. A plurality of color map selection fields may be indexed at a table to a plurality of color maps. The plurality of color maps may be based on the collected color data. Each entry of the table may include an identifier to match one of the plurality of color maps to at least one permutation of the color map selection fields.

Abstract: In one example in accordance with the present disclosure a printer cartridge and memory device containing a representation of a compressed multi-dimensional color table is described. The color table includes at least one low dimensional portion of the multi-dimensional color table storing color transformation information at a first resolution and a number of remaining portions of the multi-dimensional color table storing color transformation information at a second resolution. In the color table, the first resolution is greater than the second resolution and the at least one compressed multi-dimensional color table is to generate a high resolution uncompressed multi-dimensional color table the high resolution being at least as great as the first resolution.

Abstract: According to examples, area coverage vectors for each pixel on each slice of a digital representation of an object may be determined and a two-dimensional halftone matrix including threshold values may be subdivided into a plurality of sub-matrices, each sub-matrix including threshold values of the halftone matrix in a respective value sub-range. In addition, for each of the slices, a sub-matrix of the plurality of sub-matrices may be selected and the area coverage vectors for the pixels in the slice may be halftoned using respective threshold values of the selected sub-matrix.

Abstract: Certain examples described herein relate to producing three-dimensional objects using additive manufacturing systems. These examples combine the use of material volume coverage vectors to define object data with octree data structures and models for tracking material placement error and available volumes. Material volume coverage vectors correspond to a volumes of three-dimensional objects and define a probabilistic distribution of materials available to an additive manufacturing system including combinations of said materials. In certain examples, a bottom level of the error tracking octree model is constructed to contain at least a portion of the data values for a set of obtained material volume coverage vectors. This is then used in an error distribution process to generate manufacturing control data for the additive manufacturing system.

Abstract: In some examples, a print cartridge includes a memory device comprising quantized coefficients derived from a lossy compression, at a selected step size, of a difference color table including a plurality of difference nodes in which each difference node represents a difference value that is a difference of a value of a node of a color table and a value of a corresponding node of a reference table, the quantized coefficients useable to produce a reconstructed difference color table including a first set of difference nodes each representing a difference value that is within an error threshold at the selected step size, and a second set of difference nodes each representing a difference value that is outside an error threshold at the selected step size. The memory device further comprises corrective information to correct the second set of difference nodes of the reconstructed difference color table.

Abstract: A three-dimensional halftoning method is disclosed, wherein a halftone matrix including values is provided and subdivided into a plurality of sub-matrices, each sub-matrix including values of the halftone matrix in a respective sub-range. For a current slice of a three-dimensional representation of an object, a sub-matrix of the plurality of sub-matrices of the halftone matrix is selected and halftoning of the current slice is performed using the selected sub-matrix. Furthermore, an additive manufacturing method and system are described.

Abstract: A transform wrapper is stored on a memory device and the memory device may be included in a printer cartridge. The transform wrapper may dynamically build a transform map for a printer based on metadata stored at the memory device. The metadata may indicate at least one of a type of depositing material, transform map, print media and printer.

Abstract: In one example in accordance with the present disclosure a printer cartridge and memory device containing a representation of a compressed multi-dimensional color table is described. The color table includes at least one low dimensional portion of the multi-dimensional color table storing color transformation information at a first resolution and a number of remaining portions of the multi-dimensional color table storing color transformation information at a second resolution. In the color table, the first resolution is greater than the second resolution and the at least one compressed multi-dimensional color table is to generate a high resolution uncompressed multi-dimensional color table the high resolution being at least as great as the first resolution.

Abstract: A transform wrapper is stored on a memory device and the memory device may be included in a printer cartridge. The transform wrapper may dynamically build a transform map for a printer based on metadata stored at the memory device. The metadata may indicate at least one of a type of depositing material, transform map, print media and printer.

Abstract: Certain examples described herein relate to the processing of object data corresponding to a three-dimensional object. First data corresponding to a first portion of the three-dimensional object and second data corresponding to a second portion of the three-dimensional object, separate from the first portion, are determined. The first data is halftoned using a first halftoning technique to generate control instructions for an apparatus to produce the first portion of the three-dimensional object. The second data is halftoned using a second halftoning technique to generate control instructions for the apparatus to produce the second portion of the three-dimensional object.

Abstract: A system includes a memory to store ink-channel data that describe print resources for an ink-channel printing pipeline and Neugebauer Primary area coverage (NPac) data of an alternative printing pipeline. An NPac property stored in the memory describes a dimensional relationship between the NPac data of the alternative printing pipeline and the ink-channel data for the ink-channel printing pipeline. The system includes a processor to execute instructions stored in the memory. The instructions generate a mapping file based on the NPac property to map from an ink-channel space described by the ink-channel data to an NPac space described by the NPac data.

Abstract: In one example in accordance with the present disclosure a printer cartridge and memory device containing a representation of a compressed multi-dimensional color table is described. The color table includes at least one low dimensional portion of the multi-dimensional color table storing color transformation information at a first resolution and a number of remaining portions of the multi-dimensional color table storing color transformation information at a second resolution. In the color table, the first resolution is greater than the second resolution and the at least one compressed multi-dimensional color table is to generate a high resolution uncompressed multi-dimensional color table the high resolution being at least as great as the first resolution.

Abstract: In some examples, a print cartridge includes a memory device comprising quantized coefficients derived from a lossy compression, at a selected step size, of a difference color table including a plurality of difference nodes in which each difference node represents a difference value that is a difference of a value of a node of a color table and a value of a corresponding node of a reference table, the quantized coefficients useable to produce a reconstructed difference color table including a first set of difference nodes each representing a difference value that is within an error threshold at the selected step size, and a second set of difference nodes each representing a difference value that is outside an error threshold at the selected step size. The memory device further comprises corrective information to correct the second set of difference nodes of the reconstructed difference color table.

Abstract: Certain examples described herein relate to the processing of object data corresponding to a three-dimensional object. First data corresponding to a first portion of the three-dimensional object and second data corresponding to a second portion of the three-dimensional object, separate from the first portion, are determined. The first data is halftoned using a first halftoning technique to generate control instructions for an apparatus to produce the first portion of the three-dimensional object. The second data is halftoned using a second halftoning technique to generate control instructions for the apparatus to produce the second portion of the three-dimensional object.

Abstract: A printer cartridge includes a memory device and at least one compressed color table stored on the memory device. A compressed color table includes a losslessly compressed neutral axis, a number of nodes that correspond to seed color table nodes and a number of delta nodes that correspond to a number of delta tables. The number of delta tables indicate differences between interpolated color table nodes and corresponding actual color table nodes.