{"id":"Libpng","title":"libpng License","reviewed_on":"2026-09-22","reviewer":"Giray Havur","text_source":"https://raw.githubusercontent.com/spdx/license-list-data/main/text/Libpng.txt","text_retrieved":true,"verdict":"created","summary":"Models the libpng notice as it stood for versions 1.2.6 to 1.4.5, which is the text SPDX lists under this identifier. The operative part is three restrictions in the zlib shape: do not misrepresent the origin, mark altered versions, and leave the copyright notice alone. The record follows TheZlibLibpngLicense.","findings":[{"rubric":1,"severity":"info","field":"spdx:licenseId","description":"File name, record identifier, SPDX identifier and IRI local name are all Libpng. The library already holds the zlib text under the descriptive identifier TheZlibLibpngLicense with spdx:licenseId Zlib, and that record carries \"Libpng\" as a dct:alternative; the two are different texts and different SPDX identifiers.","action":"applied"},{"rubric":2,"severity":"info","field":"odrl:target","description":"One odrl:AssetCollection of dct:type dcmitype:Software.","action":"applied"},{"rubric":3,"severity":"major","field":"odrl:permission","description":"The grant reads \"Permission is hereby granted to use, copy, modify, and distribute this source code, or portions hereof, for any purpose, without fee, subject to the following restrictions\". The record permits reproduce, distribute, modify, derive, display, present, derivative works, modified works and the distribution fee. cc:CommercialUse rests on the separate sentence \"The Contributing Authors and Group 42, Inc. specifically permit, without fee, and encourage the use of this source code as a component to supporting the PNG file format in commercial products\".","action":"applied"},{"rubric":3,"severity":"major","field":"odrl:permission","description":"dalicc:ChangeLicense is permitted with the dalicc:compliantLicense duty. Nothing in the text bars a change of terms, and the notice condition has to survive one.","action":"applied"},{"rubric":4,"severity":"minor","field":"odrl:prohibition","description":"No prohibitions. The text has no endorsement or trademark clause. The sentence about the PNG logo files is a statement about what ships with the library, not a restriction.","action":"none"},{"rubric":5,"severity":"major","field":"odrl:duty","description":"cc:Notice hangs off odrl:distribute, odrl:modify and odrl:derive for restriction 3, \"This Copyright notice may not be removed or altered from any source or altered source distribution\". dalicc:modificationNotice and dalicc:rename hang off odrl:modify and odrl:derive for restriction 2, \"Altered versions must be plainly marked as such and must not be misrepresented as being the original source\".","action":"applied"},{"rubric":5,"severity":"minor","field":"odrl:duty","description":"No cc:Attribution. The text says \"If you use this source code in a product, acknowledgment is not required but would be appreciated\", so there is no credit duty, which is the same reading TheZlibLibpngLicense gives.","action":"applied"},{"rubric":6,"severity":"minor","field":"dalicc:WarrantyDisclaimer","description":"The disclaimer paragraph carries the warranty sentences and the liability sentence and is split at the sentence boundary. The additions to the disclaimer that the text attaches to versions 1.0.7 through 1.2.5 are quoted in dalicc:additionalClauses rather than merged into the disclaimer, because they apply to a named range of versions. The quoted clauses come from a text that wraps lines and uses two spaces after a full stop. Line breaks and repeated spaces are collapsed to a single space, which is how every other record in the library quotes a multi-line clause. No word and no punctuation mark is changed.","action":"applied"},{"rubric":7,"severity":"info","field":"cc:jurisdiction","description":"The text names no legal system and sets no term, so cc:jurisdiction is dalicc:worldwide and dalicc:validityType is dalicc:perpetual.","action":"applied"},{"rubric":8,"severity":"info","field":"dalicc:additionalClauses","description":"No clause of this text needs a term the vocabulary does not have. The per-version copyright roll and the list of contributing authors are provenance rather than terms and are not quoted.","action":"none"},{"rubric":9,"severity":"info","field":"record","description":"The consistency check of app.services.composer against the dependency graph dg_default returned an empty conflict list.","action":"none"},{"rubric":10,"severity":"info","field":"record","description":"Read against licensedata/licenses/TheZlibLibpngLicense.ttl the duty set is identical. The difference is in the clause texts and in the express sentence about commercial products, which this text has and the zlib text states inside its grant instead.","action":"none"}],"family":"Permissive variants","port_of":null,"variant_kind":null,"variant_of":null,"notes":"The text opens with the sentence that the notices in png.h prevail over this copy in case of a discrepancy; that is a statement about which copy governs and is not modelled. cc:legalcode and dct:source both point at the SPDX page, because the publisher's own address now serves version 2 of the licence."}