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https://issues.apache.org/jira/browse/TIKA-4937?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18122230#comment-18122230
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ASF GitHub Bot commented on TIKA-4937:
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dschmidt commented on PR #3266:
URL: https://github.com/apache/tika/pull/3266#issuecomment-5969144035
Thanks, all five were right. Fixed in 05b48417a1 (branch is rebased on main):
- `supported-formats.adoc` regenerated
- OS/2 bitmap arrays return early with only the content type set
- a width or height that is zero, negative or above 65535 counts as
unreadable: the directory values stand in and the image goes into the warning
- `@since` is 4.2.0, CHANGES entry added
A second review pass also turned up that a 16 bpp image was listed as 15
bpp, and that an empty directory or a header cut before the image count
produced no warning or an exception. Both are fixed in the same commit.
> Extract image dimensions and entry list from ICO/CUR files
> ----------------------------------------------------------
>
> Key: TIKA-4937
> URL: https://issues.apache.org/jira/browse/TIKA-4937
> Project: Tika
> Issue Type: New Feature
> Reporter: Dominik Schmidt
> Priority: Major
>
> h3. Background
> Tika detects {{image/vnd.microsoft.icon}} (alias {{image/x-icon}}) and
> {{ImageParser}} claims the type, but ImageIO has no ICO reader on the
> classpath, so a {{.ico}} yields nothing beyond the content type: no
> dimensions, no bit depth, no image count.
> Since TIKA-4936 every Windows EXE/DLL emits its icon groups as embedded
> {{.ico}} documents (the first one typed {{THUMBNAIL}}), so an index now sees
> plenty of .ico entries without width/height.
> h3. Proposal
> Read the ICONDIR/ICONDIRENTRY structure of {{.ico}} and {{.cur}} files
> directly (no decoding, no new dependency) and set:
> * {{tiff:ImageWidth}} / {{tiff:ImageLength}} and {{tiff:BitsPerSample}} of
> the largest image. Entries of 256 px are stored as 0 in the directory, and
> the directory's width/height/bpp fields are unreliable in general, so take
> the values from each image's header instead: the PNG IHDR for PNG-encoded
> entries, the BITMAPINFOHEADER for BMP-encoded ones (height there is doubled
> to include the AND mask).
> * the number of images
> * one multi-valued property listing each entry as {{WxH@bpp}} plus its
> encoding (bmp/png), in directory order
> * for cursors ({{.cur}}, type 2 in the header): the hotspot of the largest
> image
> No text content. Malformed files (directory beyond EOF, entry offsets outside
> the file, count 0, unknown encoding) must not throw: emit what can be read
> and record a warning.
> Implementation: a dedicated small parser in {{tika-parser-image-module}} for
> {{image/vnd.microsoft.icon}} and {{image/x-win-bitmap}}, replacing the
> {{image/x-icon}} entry in {{ImageParser}}'s supported types (which currently
> finds no reader).
> h3. Out of scope
> * Decoding or rendering the images (the thumbnail presets keep passing the
> .ico through as stored)
> * Animated cursors ({{.ani}}), {{RT_GROUP_CURSOR}} extraction from PE files
> h3. Acceptance criteria
> * {{tika -m}} on a .ico with 16/32 px BMP entries and a 256 px PNG entry
> reports 256x256, 32 bpp, 3 images and the per-entry list.
> * The embedded icons of TIKA-4936's fixtures show width/height in {{/rmeta}}
> output.
> * A .cur reports type cursor and the hotspot.
> * Truncated or corrupt .ico files yield a warning, not an exception.
> * Fixtures: {{testWindows-icons-app.ico}} / {{-doc.ico}} from TIKA-4936 plus
> one generated .cur.
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