521 lines
20 KiB
Plaintext
521 lines
20 KiB
Plaintext
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PNGSUITE
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----------------
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testset for PNG-(de)coders
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created by Willem van Schaik
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------------------------------------
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This is a collection of graphics images created to test the png applications
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like viewers, converters and editors. All (as far as that is possible)
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formats supported by the PNG standard are represented.
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1. INTRODUCTION
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--------------------
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1.1 PNG capabilities
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------------------------
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Supported color-types are:
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- grayscale
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- grayscale + alpha-channel
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- color palettes
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- rgb
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- rgb + alpha-channel
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Allowed bitdepths are depending on the color-type, but are in the range
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of 1-bit (grayscale, which is b&w) upto 16-bits.
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Special features are:
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- interlacing (Adam-7)
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- gamma-support
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- transparency (a poor-man's alpha solution)
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1.2 File naming
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-------------------
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Where possible, the testfiles are 32x32 bits icons. This results in a still
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reasonable size of the suite even with a large number of tests. The name
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of each test-file reflects thetype in the following way:
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g04i2c08.png
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|| |||+---- bit-depth
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|| ||+----- color-type (descriptive)
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|| |+------ color-type (numerical)
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|| +------- interlaced or non-interlaced
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|+--------- parameter of test (in this case gamma-value)
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+---------- test feature (in this case gamma)
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1.3 PNG formats
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-------------------
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color-type:
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0g - grayscale
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2c - rgb color
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3p - paletted
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4a - grayscale + alpha channel
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6a - rgb color + alpha channel
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bit-depth:
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01 - with color-type 0, 3
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02 - with color-type 0, 3
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04 - with color-type 0, 3
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08 - with color-type 0, 2, 3, 4, 6
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16 - with color-type 0, 2, 4, 6
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interlacing:
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n - non-interlaced
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i - interlaced
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2. THE TESTS
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-----------------
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2.1 Sizes
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-------------
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These tests are there to check if your software handles pictures well, with
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picture sizes that are not a multiple of 8. This is particularly important
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with Adam-7 type interlacing. In the same way these tests check if pictures
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size 1x1 and similar are ok.
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s01 - 1x1 pixel picture
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s02 - 2x2 pixel picture
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s03 - 3x3 pixel picture
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s04 - 4x4 pixel picture
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s05 - 5x5 pixel picture
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s06 - 6x6 pixel picture
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s07 - 7x7 pixel picture
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s08 - 8x8 pixel picture
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s09 - 9x9 pixel picture
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s32 - 32x32 pixel picture
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s33 - 33x33 pixel picture
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s34 - 34x34 pixel picture
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s35 - 35x35 pixel picture
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s36 - 36x36 pixel picture
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s37 - 37x37 pixel picture
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s38 - 38x38 pixel picture
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s39 - 39x39 pixel picture
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s40 - 40x40 pixel picture
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2.2 Background
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------------------
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When the PNG file contains a background chunck, this should be used for
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pictures with alpha-channel or pictures with a transparency chunck. For
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pictures without this background-chunk, but with alpha, this testset
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assumes a black background.
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For the images in this test, the left-side should be 100% the background
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color, where moving to the right the color should gradually become the
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image pattern.
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bga - alpha + no background
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bgw - alpha + white background
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bgg - alpha + gray background
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bgb - alpha + black background
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bgy - alpha + yellow background
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2.3 Transparency
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--------------------
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Transparency should be used together with a background chunk. To test the
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combination of the two the latter 4 tests are there. How to handle pictures
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with transparancy, but without a background, opinions can differ. Here we
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use black, but especially in the case of paletted images, the normal color
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would maybe even be better.
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tp0 - not transparent for reference
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tp1 - transparent, but no background chunk
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tbw - transparent + white background
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tbg - transparent + gray background
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tbb - transparent + black background
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tby - transparent + yellow background
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2.4 Gamma
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-------------
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To test if your viewer handles gamma-correction, 6 testfiles are available.
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They contain corrected color-ramps and a corresponding gamma-chunk with the
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file-gamma value. These are created in such a way that when the viewer does
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the gamma correction right, all 6 should be displayed identical.
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If they are different, probably the gamma correction is omitted. In that
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case, have a look at the two right coloumns in the 6 pictures. The image
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where those two look the same (when looked from far) reflects the gamma of
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your system. However, because of the limited size of the image, you should
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do more elaborate tests to determine your display gamma.
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g03 - file-gamma = 0.35, for display with gamma = 2.8
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g04 - file-gamma = 0.45, for display with gamma = 2.2 (PC)
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g05 - file-gamma = 0.55, for display with gamma = 1.8 (Mac)
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g07 - file-gamma = 0.70, for display with gamma = 1.4
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g10 - file-gamma = 1.00, for display with gamma = 1.0 (NeXT)
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g25 - file-gamma = 2.50, for display with gamma = 0.4
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2.5 Filtering
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-----------------
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PNG uses file-filtering, for optimal compression. Normally the type is of
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filtering is adjusted to the contents of the picture, but here each file
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has the same picture, with a different filtering.
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f0 - no filtering
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f1 - sub filtering
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f2 - up filtering
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f3 - average filtering
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f4 - paeth filtering
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2.6 Additional palettes
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---------------------------
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Besides the normal use of paletted images, palette chunks can in combination
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with true-color (and other) images also be used to select color lookup-tables
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when the video system is of limited capabilities. The suggested palette chunk
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is specially created for this purpose.
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pp - normal palette chunk
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ps - suggested palette chunk
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2.7 Ancillary chunks (under construction)
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------------------------
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To test the correct decoding of ancillary chunks, these test-files contain
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one or more examples of these chunkcs. Depending on the type of chunk, a
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number of typical values are selected to test. Unluckily, the testset can
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not contain all combinations, because that would be an endless set.
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The significant bits are used in files with the next higher bit-depth. They
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indicate howmany bits are valid.
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cs3 - 3 significant bits
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cs5 - 5 significant bits
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cs8 - 8 significant bits (reference)
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cs3 - 13 significant bits
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For the physical pixel dimensions, the result of each decoding should be
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a sqare picture. The first (cdf) image is an example of flat (horizontal)
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pixels, where the pHYS chunk (x is 1 per unit, y = 4 per unit) must take
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care of the correction. The second is just the other way round. The last
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example uses the unit specifier, for 1000 pixels per meter. This should
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result in a picture of 3.2 cm square.
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cdf - physical pixel dimensions, 8x32 flat pixels
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cdh - physical pixel dimensions, 32x8 high pixels
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cds - physical pixel dimensions, 8x8 square pixels
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cdu - physical pixel dimensions, with unit-specifier
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ccw - primary chromaticities and white point
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ch1 - histogram 15 colors
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ch2 - histogram 256 colors
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cm7 - modification time, 01-jan-1970
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cm9 - modification time, 31-dec-1999
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cm0 - modification time, 01-jan-2000
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In the textual chunk, a number of the standard, and some non-standard
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text items are included.
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ct0 - no textual data
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ct1 - with textual data
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ctz - with compressed textual data
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2.8 Chunk ordering (still under construction)
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----------------------
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These testfiles will test the obligatory ordering relations between various
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chunk types (not yet) as well as the number of data chunks used for the image.
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oi1 - mother image with 1 idat-chunk
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oi2 - image with 2 idat-chunks
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oi4 - image with 4 unequal sized idat-chunks
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oi9 - all idat-chunks of length one
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2.9 Compression level
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-------------------------
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Here you will find a set of images compressed by zlib, ranging from level 0
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for no compression at maximum speed upto level 9 for maximum compression.
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z00 - zlib compression level 0 - none
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z03 - zlib compression level 3
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z06 - zlib compression level 6 - default
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z09 - zlib compression level 9 - maximum
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2.10 Corrupted files (under construction)
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-----------------------
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All these files are illegal. When decoding they should generate appropriate
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error-messages.
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x00 - empty IDAT chunk
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xcr - added cr bytes
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xlf - added lf bytes
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xc0 - color type 0
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xc9 - color type 9
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xd0 - bit-depth 0
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xd3 - bit-depth 3
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xd9 - bit-depth 99
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xcs - incorrect IDAT checksum
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3. TEST FILES
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------------------
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For each of the tests listed above, one or more test-files are created. A
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selection is made (for each test) for the color-type and bitdepth to be used
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for the tests. Further for a number of tests, both a non-interlaced as well
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as an interlaced version is available.
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3.1 Basic format test files (non-interlaced)
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------------------------------------------------
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basn0g01 - black & white
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basn0g02 - 2 bit (4 level) grayscale
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basn0g04 - 4 bit (16 level) grayscale
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basn0g08 - 8 bit (256 level) grayscale
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basn0g16 - 16 bit (64k level) grayscale
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basn2c08 - 3x8 bits rgb color
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basn2c16 - 3x16 bits rgb color
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basn3p01 - 1 bit (2 color) paletted
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basn3p02 - 2 bit (4 color) paletted
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basn3p04 - 4 bit (16 color) paletted
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basn3p08 - 8 bit (256 color) paletted
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basn4a08 - 8 bit grayscale + 8 bit alpha-channel
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basn4a16 - 16 bit grayscale + 16 bit alpha-channel
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basn6a08 - 3x8 bits rgb color + 8 bit alpha-channel
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basn6a16 - 3x16 bits rgb color + 16 bit alpha-channel
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3.2 Basic format test files (Adam-7 interlaced)
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---------------------------------------------------
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basi0g01 - black & white
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basi0g02 - 2 bit (4 level) grayscale
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basi0g04 - 4 bit (16 level) grayscale
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basi0g08 - 8 bit (256 level) grayscale
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basi0g16 - 16 bit (64k level) grayscale
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basi2c08 - 3x8 bits rgb color
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basi2c16 - 3x16 bits rgb color
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basi3p01 - 1 bit (2 color) paletted
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basi3p02 - 2 bit (4 color) paletted
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basi3p04 - 4 bit (16 color) paletted
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basi3p08 - 8 bit (256 color) paletted
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basi4a08 - 8 bit grayscale + 8 bit alpha-channel
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basi4a16 - 16 bit grayscale + 16 bit alpha-channel
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basi6a08 - 3x8 bits rgb color + 8 bit alpha-channel
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basi6a16 - 3x16 bits rgb color + 16 bit alpha-channel
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3.3 Sizes test files
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-----------------------
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s01n3p01 - 1x1 paletted file, no interlacing
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s02n3p01 - 2x2 paletted file, no interlacing
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s03n3p01 - 3x3 paletted file, no interlacing
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s04n3p01 - 4x4 paletted file, no interlacing
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s05n3p02 - 5x5 paletted file, no interlacing
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s06n3p02 - 6x6 paletted file, no interlacing
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s07n3p02 - 7x7 paletted file, no interlacing
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s08n3p02 - 8x8 paletted file, no interlacing
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s09n3p02 - 9x9 paletted file, no interlacing
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s32n3p04 - 32x32 paletted file, no interlacing
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s33n3p04 - 33x33 paletted file, no interlacing
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s34n3p04 - 34x34 paletted file, no interlacing
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s35n3p04 - 35x35 paletted file, no interlacing
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s36n3p04 - 36x36 paletted file, no interlacing
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s37n3p04 - 37x37 paletted file, no interlacing
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s38n3p04 - 38x38 paletted file, no interlacing
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s39n3p04 - 39x39 paletted file, no interlacing
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s40n3p04 - 40x40 paletted file, no interlacing
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s01i3p01 - 1x1 paletted file, interlaced
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s02i3p01 - 2x2 paletted file, interlaced
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s03i3p01 - 3x3 paletted file, interlaced
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s04i3p01 - 4x4 paletted file, interlaced
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s05i3p02 - 5x5 paletted file, interlaced
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s06i3p02 - 6x6 paletted file, interlaced
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s07i3p02 - 7x7 paletted file, interlaced
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s08i3p02 - 8x8 paletted file, interlaced
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s09i3p02 - 9x9 paletted file, interlaced
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s32i3p04 - 32x32 paletted file, interlaced
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s33i3p04 - 33x33 paletted file, interlaced
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s34i3p04 - 34x34 paletted file, interlaced
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s35i3p04 - 35x35 paletted file, interlaced
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s36i3p04 - 36x36 paletted file, interlaced
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s37i3p04 - 37x37 paletted file, interlaced
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s38i3p04 - 38x38 paletted file, interlaced
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s39i3p04 - 39x39 paletted file, interlaced
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s40i3p04 - 40x40 paletted file, interlaced
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3.4 Background test files (with alpha)
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------------------------------------------
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bgai4a08 - 8 bit grayscale, alpha, no background chunk, interlaced
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bgai4a16 - 16 bit grayscale, alpha, no background chunk, interlaced
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bgan6a08 - 3x8 bits rgb color, alpha, no background chunk
|
||
|
|
bgan6a16 - 3x16 bits rgb color, alpha, no background chunk
|
||
|
|
|
||
|
|
bgbn4a08 - 8 bit grayscale, alpha, black background chunk
|
||
|
|
bggn4a16 - 16 bit grayscale, alpha, gray background chunk
|
||
|
|
bgwn6a08 - 3x8 bits rgb color, alpha, white background chunk
|
||
|
|
bgyn6a16 - 3x16 bits rgb color, alpha, yellow background chunk
|
||
|
|
|
||
|
|
|
||
|
|
3.5 Transparency (and background) test files
|
||
|
|
------------------------------------------------
|
||
|
|
|
||
|
|
tp0n1g08 - not transparent for reference (logo on gray)
|
||
|
|
tbbn1g04 - transparent, black background chunk
|
||
|
|
tbwn1g16 - transparent, white background chunk
|
||
|
|
tp0n2c08 - not transparent for reference (logo on gray)
|
||
|
|
tbrn2c08 - transparent, red background chunk
|
||
|
|
tbgn2c16 - transparent, green background chunk
|
||
|
|
tbbn2c16 - transparent, blue background chunk
|
||
|
|
tp0n3p08 - not transparent for reference (logo on gray)
|
||
|
|
tp1n3p08 - transparent, but no background chunk
|
||
|
|
tbbn3p08 - transparent, black background chunk
|
||
|
|
tbgn3p08 - transparent, light-gray background chunk
|
||
|
|
tbwn3p08 - transparent, white background chunk
|
||
|
|
tbyn3p08 - transparent, yellow background chunk
|
||
|
|
|
||
|
|
|
||
|
|
3.6 Gamma test files
|
||
|
|
------------------------
|
||
|
|
|
||
|
|
g03n0g16 - grayscale, file-gamma = 0.35
|
||
|
|
g04n0g16 - grayscale, file-gamma = 0.45
|
||
|
|
g05n0g16 - grayscale, file-gamma = 0.55
|
||
|
|
g07n0g16 - grayscale, file-gamma = 0.70
|
||
|
|
g10n0g16 - grayscale, file-gamma = 1.00
|
||
|
|
g25n0g16 - grayscale, file-gamma = 2.50
|
||
|
|
g03n2c08 - color, file-gamma = 0.35
|
||
|
|
g04n2c08 - color, file-gamma = 0.45
|
||
|
|
g05n2c08 - color, file-gamma = 0.55
|
||
|
|
g07n2c08 - color, file-gamma = 0.70
|
||
|
|
g10n2c08 - color, file-gamma = 1.00
|
||
|
|
g25n2c08 - color, file-gamma = 2.50
|
||
|
|
g03n3p04 - paletted, file-gamma = 0.35
|
||
|
|
g04n3p04 - paletted, file-gamma = 0.45
|
||
|
|
g05n3p04 - paletted, file-gamma = 0.55
|
||
|
|
g07n3p04 - paletted, file-gamma = 0.70
|
||
|
|
g10n3p04 - paletted, file-gamma = 1.00
|
||
|
|
g25n3p04 - paletted, file-gamma = 2.50
|
||
|
|
|
||
|
|
|
||
|
|
3.7 Filtering test files
|
||
|
|
----------------------------
|
||
|
|
|
||
|
|
f00n0g08 - grayscale, no interlacing, filter-type 0
|
||
|
|
f01n0g08 - grayscale, no interlacing, filter-type 1
|
||
|
|
f02n0g08 - grayscale, no interlacing, filter-type 2
|
||
|
|
f03n0g08 - grayscale, no interlacing, filter-type 3
|
||
|
|
f04n0g08 - grayscale, no interlacing, filter-type 4
|
||
|
|
f00n2c08 - color, no interlacing, filter-type 0
|
||
|
|
f01n2c08 - color, no interlacing, filter-type 1
|
||
|
|
f02n2c08 - color, no interlacing, filter-type 2
|
||
|
|
f03n2c08 - color, no interlacing, filter-type 3
|
||
|
|
f04n2c08 - color, no interlacing, filter-type 4
|
||
|
|
|
||
|
|
|
||
|
|
3.8 Additional palette chunk test files
|
||
|
|
-------------------------------------------
|
||
|
|
|
||
|
|
pp0n2c16 - six-cube palette-chunk in true-color image
|
||
|
|
pp0n6a08 - six-cube palette-chunk in true-color+alpha image
|
||
|
|
ps1n0g08 - six-cube suggested palette (1 byte) in grayscale image
|
||
|
|
ps1n2c16 - six-cube suggested palette (1 byte) in true-color image
|
||
|
|
ps2n0g08 - six-cube suggested palette (2 bytes) in grayscale image
|
||
|
|
ps2n2c16 - six-cube suggested palette (2 bytes) in true-color image
|
||
|
|
|
||
|
|
|
||
|
|
3.9 Ancillary chunks test files
|
||
|
|
-----------------------------------
|
||
|
|
|
||
|
|
cs5n2c08 - color, 5 significant bits
|
||
|
|
cs8n2c08 - color, 8 significant bits (reference)
|
||
|
|
cs3n2c16 - color, 13 significant bits
|
||
|
|
cs3n3p08 - paletted, 3 significant bits
|
||
|
|
cs5n3p08 - paletted, 5 significant bits
|
||
|
|
cs8n3p08 - paletted, 8 significant bits (reference)
|
||
|
|
|
||
|
|
cdfn2c08 - physical pixel dimensions, 8x32 flat pixels
|
||
|
|
cdhn2c08 - physical pixel dimensions, 32x8 high pixels
|
||
|
|
cdsn2c08 - physical pixel dimensions, 8x8 square pixels
|
||
|
|
cdun2c08 - physical pixel dimensions, 1000 pixels per 1 meter
|
||
|
|
|
||
|
|
ccwn2c08 - chroma chunk w:0.3127,0.3290 r:0.64,0.33 g:0.30,0.60 b:0.15,0.06
|
||
|
|
ccwn3p08 - chroma chunk w:0.3127,0.3290 r:0.64,0.33 g:0.30,0.60 b:0.15,0.06
|
||
|
|
|
||
|
|
ch1n3p04 - histogram 15 colors
|
||
|
|
ch2n3p08 - histogram 256 colors
|
||
|
|
|
||
|
|
cm7n0g04 - modification time, 01-jan-1970 00:00:00
|
||
|
|
cm9n0g04 - modification time, 31-dec-1999 23:59:59
|
||
|
|
cm0n0g04 - modification time, 01-jan-2000 12:34:56
|
||
|
|
|
||
|
|
ct0n0g04 - no textual data
|
||
|
|
ct1n0g04 - with textual data
|
||
|
|
ctzn0g04 - with compressed textual data
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
3.10 Chunk ordering
|
||
|
|
----------------------
|
||
|
|
|
||
|
|
oi1n0g16 - grayscale mother image with 1 idat-chunk
|
||
|
|
oi2n0g16 - grayscale image with 2 idat-chunks
|
||
|
|
oi4n0g16 - grayscale image with 4 unequal sized idat-chunks
|
||
|
|
oi9n0g16 - grayscale image with all idat-chunks length one
|
||
|
|
oi1n2c16 - color mother image with 1 idat-chunk
|
||
|
|
oi2n2c16 - color image with 2 idat-chunks
|
||
|
|
oi4n2c16 - color image with 4 unequal sized idat-chunks
|
||
|
|
oi9n2c16 - color image with all idat-chunks length one
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
3.11 Compression level
|
||
|
|
-------------------------
|
||
|
|
|
||
|
|
z00n2c08 - color, no interlacing, compression level 0 (none)
|
||
|
|
z03n2c08 - color, no interlacing, compression level 3
|
||
|
|
z06n2c08 - color, no interlacing, compression level 6 (default)
|
||
|
|
z09n2c08 - color, no interlacing, compression level 9 (maximum)
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
3.12 Currupted files
|
||
|
|
-----------------------
|
||
|
|
|
||
|
|
x00n0g01 - empty 0x0 grayscale file
|
||
|
|
xcrn0g04 - added cr bytes
|
||
|
|
xlfn0g04 - added lf bytes
|
||
|
|
xc0n0c08 - color type 0
|
||
|
|
xc9n0c08 - color type 9
|
||
|
|
xd0n2c00 - bit-depth 0
|
||
|
|
xd3n2c03 - bit-depth 3
|
||
|
|
xd9n2c99 - bit-depth 99
|
||
|
|
xcsn2c08 - incorrect IDAT checksum
|
||
|
|
|
||
|
|
|
||
|
|
--------
|
||
|
|
(c) Willem van Schaik
|
||
|
|
willem@schaik.com
|
||
|
|
Singapore, October 1996
|