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Questions on processing .rgb(a) files

Posted: 2012-12-03T23:40:42-07:00
by Zjar
Hello everyone

I have a number of .rgb and .rgba files which I would like to modify, specifically change brightness and contrast. This is what identify tells me about the images (same info for rgb and rgba):
identify image.rgba
image.rgba SGI 64x32 64x32+0+0 8-bit sRGB 256c 4.61KB 0.000u 0:00.000
Working with rgb files haven't been much of an issue, I can process them just fine. However, the generated image has a larger filesize than the original, which I think comes from the image having a larger color-palette. The original image seems to have a 256 color palette defined whereas the generated ones have something else (and larger). How can I specify the palette for the generated images?

Ok, that was only a minor issue. My main issue is with processing rgba files. I have not been able to preserve transparency in the generated images, so the images are simply turned to plain rgb files. I've invoked convert in many ways, but always something similar to:
convert -brightness-contrast 15x5 sgi:image.rgba sgi:generated/image.rgba
So how can I preserve alpha value / output rgba files?

Thanks for your answers!

Re: Questions on processing .rgb(a) files

Posted: 2012-12-04T11:47:52-07:00
by fmw42
convert -brightness-contrast 15x5 sgi:image.rgba sgi:generated/image.rgba
try putting the input image before the options

convert sgi:image.rgba -alpha off -brightness-contrast 15x5 -alpha on sgi:generated/image.rgba

Re: Questions on processing .rgb(a) files

Posted: 2012-12-04T23:48:29-07:00
by Zjar
Hello fmw42 and thanks for your advice. Unfortunately it didn't work, transparency was seemingly not preserved in the generated image.

I suppose it would be best if I uploaded an image for people to test with. An image can be downloaded from here: http://speedy.sh/gPzgE/image.rgba Click on the large text "Download image.rgba".

Hmm, while we're at it, what's a good file-hosting website for things like this?

Re: Questions on processing .rgb(a) files

Posted: 2012-12-05T11:37:59-07:00
by fmw42
IM 6.8.0.7 Q16 Mac OSX Snow Leopard

IM is not recognizing this format properly. When I display it in IM all I get is a solid gray (1 color image) with no transparency as is shown by the verbose info:


Image: image.rgba
Format: SGI (Irix RGB image)
Class: PseudoClass
Geometry: 128x128+0+0
Units: Undefined
Type: Palette
Endianess: Undefined
Colorspace: sRGB
Depth: 8-bit
Channel depth:
red: 8-bit
green: 8-bit
blue: 8-bit
Channel statistics:
Red:
min: 240 (0.941176)
max: 240 (0.941176)
mean: 240 (0.941176)
standard deviation: 0 (0)
kurtosis: 0
skewness: 0
Green:
min: 240 (0.941176)
max: 240 (0.941176)
mean: 240 (0.941176)
standard deviation: 0 (0)
kurtosis: 0
skewness: 0
Blue:
min: 240 (0.941176)
max: 240 (0.941176)
mean: 240 (0.941176)
standard deviation: 0 (0)
kurtosis: 0
skewness: 0
Image statistics:
Overall:
min: 240 (0.941176)
max: 240 (0.941176)
mean: 240 (0.941176)
standard deviation: 0 (0)
kurtosis: 0
skewness: 0
Colors: 1
Histogram:
16384: (240,240,240) #F0F0F0 grey94


However, it does open fine in GaphicConverter as is a fuzzy yellow circle in the middle of a red background. But again it does not indicate that there is any transparency.

You may want to check the tool that created this to see if it is creating it according to proper specs. Otherwise, report this on the Bugs forum as clearly, IM is not getting even the color information.

Re: Questions on processing .rgb(a) files

Posted: 2012-12-06T00:16:48-07:00
by Zjar
I also got ImageMagick 6.8.0-7 2012-11-30 Q16, on Ubuntu Linux. This is the output of 'identify -verbose' on the image for me:

(Maybe it would be an idea to post the information for the generated image as well?)

Code: Select all

Image: image.rgba
  Format: SGI (Irix RGB image)
  Class: PseudoClass
  Geometry: 128x128+0+0
  Units: Undefined
  Type: Palette
  Endianess: Undefined
  Colorspace: sRGB
  Depth: 8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Red:
      min: 240 (0.941176)
      max: 240 (0.941176)
      mean: 240 (0.941176)
      standard deviation: 0 (0)
      kurtosis: 0
      skewness: 0
    Green:
      min: 240 (0.941176)
      max: 240 (0.941176)
      mean: 240 (0.941176)
      standard deviation: 0 (0)
      kurtosis: 0
      skewness: 0
    Blue:
      min: 240 (0.941176)
      max: 240 (0.941176)
      mean: 240 (0.941176)
      standard deviation: 0 (0)
      kurtosis: 0
      skewness: 0
  Image statistics:
    Overall:
      min: 240 (0.941176)
      max: 240 (0.941176)
      mean: 240 (0.941176)
      standard deviation: 0 (0)
      kurtosis: 0
      skewness: 0
  Colors: 1
  Histogram:
     16384: (240,240,240) #F0F0F0 grey94
  Colormap: 256
         0: (  0,  0,  0) #000000 black
         1: (  1,  1,  1) #010101 srgb(1,1,1)
         2: (  2,  2,  2) #020202 srgb(2,2,2)
         3: (  3,  3,  3) #030303 grey1
         4: (  4,  4,  4) #040404 srgb(4,4,4)
         5: (  5,  5,  5) #050505 grey2
         6: (  6,  6,  6) #060606 srgb(6,6,6)
         7: (  7,  7,  7) #070707 srgb(7,7,7)
         8: (  8,  8,  8) #080808 grey3
         9: (  9,  9,  9) #090909 srgb(9,9,9)
        10: ( 10, 10, 10) #0A0A0A grey4
        11: ( 11, 11, 11) #0B0B0B srgb(11,11,11)
        12: ( 12, 12, 12) #0C0C0C srgb(12,12,12)
        13: ( 13, 13, 13) #0D0D0D grey5
        14: ( 14, 14, 14) #0E0E0E srgb(14,14,14)
        15: ( 15, 15, 15) #0F0F0F grey6
        16: ( 16, 16, 16) #101010 srgb(16,16,16)
        17: ( 17, 17, 17) #111111 srgb(17,17,17)
        18: ( 18, 18, 18) #121212 grey7
        19: ( 19, 19, 19) #131313 srgb(19,19,19)
        20: ( 20, 20, 20) #141414 grey8
        21: ( 21, 21, 21) #151515 srgb(21,21,21)
        22: ( 22, 22, 22) #161616 srgb(22,22,22)
        23: ( 23, 23, 23) #171717 grey9
        24: ( 24, 24, 24) #181818 srgb(24,24,24)
        25: ( 25, 25, 25) #191919 srgb(25,25,25)
        26: ( 26, 26, 26) #1A1A1A grey10
        27: ( 27, 27, 27) #1B1B1B srgb(27,27,27)
        28: ( 28, 28, 28) #1C1C1C grey11
        29: ( 29, 29, 29) #1D1D1D srgb(29,29,29)
        30: ( 30, 30, 30) #1E1E1E srgb(30,30,30)
        31: ( 31, 31, 31) #1F1F1F grey12
        32: ( 32, 32, 32) #202020 srgb(32,32,32)
        33: ( 33, 33, 33) #212121 grey13
        34: ( 34, 34, 34) #222222 srgb(34,34,34)
        35: ( 35, 35, 35) #232323 srgb(35,35,35)
        36: ( 36, 36, 36) #242424 grey14
        37: ( 37, 37, 37) #252525 srgb(37,37,37)
        38: ( 38, 38, 38) #262626 grey15
        39: ( 39, 39, 39) #272727 srgb(39,39,39)
        40: ( 40, 40, 40) #282828 srgb(40,40,40)
        41: ( 41, 41, 41) #292929 grey16
        42: ( 42, 42, 42) #2A2A2A srgb(42,42,42)
        43: ( 43, 43, 43) #2B2B2B grey17
        44: ( 44, 44, 44) #2C2C2C srgb(44,44,44)
        45: ( 45, 45, 45) #2D2D2D srgb(45,45,45)
        46: ( 46, 46, 46) #2E2E2E grey18
        47: ( 47, 47, 47) #2F2F2F srgb(47,47,47)
        48: ( 48, 48, 48) #303030 grey19
        49: ( 49, 49, 49) #313131 srgb(49,49,49)
        50: ( 50, 50, 50) #323232 srgb(50,50,50)
        51: ( 51, 51, 51) #333333 grey20
        52: ( 52, 52, 52) #343434 srgb(52,52,52)
        53: ( 53, 53, 53) #353535 srgb(53,53,53)
        54: ( 54, 54, 54) #363636 grey21
        55: ( 55, 55, 55) #373737 srgb(55,55,55)
        56: ( 56, 56, 56) #383838 grey22
        57: ( 57, 57, 57) #393939 srgb(57,57,57)
        58: ( 58, 58, 58) #3A3A3A srgb(58,58,58)
        59: ( 59, 59, 59) #3B3B3B grey23
        60: ( 60, 60, 60) #3C3C3C srgb(60,60,60)
        61: ( 61, 61, 61) #3D3D3D grey24
        62: ( 62, 62, 62) #3E3E3E srgb(62,62,62)
        63: ( 63, 63, 63) #3F3F3F srgb(63,63,63)
        64: ( 64, 64, 64) #404040 grey25
        65: ( 65, 65, 65) #414141 srgb(65,65,65)
        66: ( 66, 66, 66) #424242 grey26
        67: ( 67, 67, 67) #434343 srgb(67,67,67)
        68: ( 68, 68, 68) #444444 srgb(68,68,68)
        69: ( 69, 69, 69) #454545 grey27
        70: ( 70, 70, 70) #464646 srgb(70,70,70)
        71: ( 71, 71, 71) #474747 grey28
        72: ( 72, 72, 72) #484848 srgb(72,72,72)
        73: ( 73, 73, 73) #494949 srgb(73,73,73)
        74: ( 74, 74, 74) #4A4A4A grey29
        75: ( 75, 75, 75) #4B4B4B srgb(75,75,75)
        76: ( 76, 76, 76) #4C4C4C srgb(76,76,76)
        77: ( 77, 77, 77) #4D4D4D grey30
        78: ( 78, 78, 78) #4E4E4E srgb(78,78,78)
        79: ( 79, 79, 79) #4F4F4F grey31
        80: ( 80, 80, 80) #505050 srgb(80,80,80)
        81: ( 81, 81, 81) #515151 srgb(81,81,81)
        82: ( 82, 82, 82) #525252 grey32
        83: ( 83, 83, 83) #535353 srgb(83,83,83)
        84: ( 84, 84, 84) #545454 grey33
        85: ( 85, 85, 85) #555555 srgb(85,85,85)
        86: ( 86, 86, 86) #565656 srgb(86,86,86)
        87: ( 87, 87, 87) #575757 grey34
        88: ( 88, 88, 88) #585858 srgb(88,88,88)
        89: ( 89, 89, 89) #595959 grey35
        90: ( 90, 90, 90) #5A5A5A srgb(90,90,90)
        91: ( 91, 91, 91) #5B5B5B srgb(91,91,91)
        92: ( 92, 92, 92) #5C5C5C grey36
        93: ( 93, 93, 93) #5D5D5D srgb(93,93,93)
        94: ( 94, 94, 94) #5E5E5E grey37
        95: ( 95, 95, 95) #5F5F5F srgb(95,95,95)
        96: ( 96, 96, 96) #606060 srgb(96,96,96)
        97: ( 97, 97, 97) #616161 grey38
        98: ( 98, 98, 98) #626262 srgb(98,98,98)
        99: ( 99, 99, 99) #636363 grey39
       100: (100,100,100) #646464 srgb(100,100,100)
       101: (101,101,101) #656565 srgb(101,101,101)
       102: (102,102,102) #666666 grey40
       103: (103,103,103) #676767 srgb(103,103,103)
       104: (104,104,104) #686868 srgb(104,104,104)
       105: (105,105,105) #696969 DimGray
       106: (106,106,106) #6A6A6A srgb(106,106,106)
       107: (107,107,107) #6B6B6B grey42
       108: (108,108,108) #6C6C6C srgb(108,108,108)
       109: (109,109,109) #6D6D6D srgb(109,109,109)
       110: (110,110,110) #6E6E6E grey43
       111: (111,111,111) #6F6F6F srgb(111,111,111)
       112: (112,112,112) #707070 grey44
       113: (113,113,113) #717171 srgb(113,113,113)
       114: (114,114,114) #727272 srgb(114,114,114)
       115: (115,115,115) #737373 grey45
       116: (116,116,116) #747474 srgb(116,116,116)
       117: (117,117,117) #757575 grey46
       118: (118,118,118) #767676 srgb(118,118,118)
       119: (119,119,119) #777777 srgb(119,119,119)
       120: (120,120,120) #787878 grey47
       121: (121,121,121) #797979 srgb(121,121,121)
       122: (122,122,122) #7A7A7A grey48
       123: (123,123,123) #7B7B7B srgb(123,123,123)
       124: (124,124,124) #7C7C7C srgb(124,124,124)
       125: (125,125,125) #7D7D7D grey49
       126: (126,126,126) #7E7E7E gray
       127: (127,127,127) #7F7F7F grey50
       128: (128,128,128) #808080 fractal
       129: (129,129,129) #818181 srgb(129,129,129)
       130: (130,130,130) #828282 grey51
       131: (131,131,131) #838383 srgb(131,131,131)
       132: (132,132,132) #848484 srgb(132,132,132)
       133: (133,133,133) #858585 grey52
       134: (134,134,134) #868686 srgb(134,134,134)
       135: (135,135,135) #878787 grey53
       136: (136,136,136) #888888 srgb(136,136,136)
       137: (137,137,137) #898989 srgb(137,137,137)
       138: (138,138,138) #8A8A8A grey54
       139: (139,139,139) #8B8B8B srgb(139,139,139)
       140: (140,140,140) #8C8C8C grey55
       141: (141,141,141) #8D8D8D srgb(141,141,141)
       142: (142,142,142) #8E8E8E srgb(142,142,142)
       143: (143,143,143) #8F8F8F grey56
       144: (144,144,144) #909090 srgb(144,144,144)
       145: (145,145,145) #919191 grey57
       146: (146,146,146) #929292 srgb(146,146,146)
       147: (147,147,147) #939393 srgb(147,147,147)
       148: (148,148,148) #949494 grey58
       149: (149,149,149) #959595 srgb(149,149,149)
       150: (150,150,150) #969696 grey59
       151: (151,151,151) #979797 srgb(151,151,151)
       152: (152,152,152) #989898 srgb(152,152,152)
       153: (153,153,153) #999999 grey60
       154: (154,154,154) #9A9A9A srgb(154,154,154)
       155: (155,155,155) #9B9B9B srgb(155,155,155)
       156: (156,156,156) #9C9C9C grey61
       157: (157,157,157) #9D9D9D srgb(157,157,157)
       158: (158,158,158) #9E9E9E grey62
       159: (159,159,159) #9F9F9F srgb(159,159,159)
       160: (160,160,160) #A0A0A0 srgb(160,160,160)
       161: (161,161,161) #A1A1A1 grey63
       162: (162,162,162) #A2A2A2 srgb(162,162,162)
       163: (163,163,163) #A3A3A3 grey64
       164: (164,164,164) #A4A4A4 srgb(164,164,164)
       165: (165,165,165) #A5A5A5 srgb(165,165,165)
       166: (166,166,166) #A6A6A6 grey65
       167: (167,167,167) #A7A7A7 srgb(167,167,167)
       168: (168,168,168) #A8A8A8 grey66
       169: (169,169,169) #A9A9A9 DarkGray
       170: (170,170,170) #AAAAAA srgb(170,170,170)
       171: (171,171,171) #ABABAB grey67
       172: (172,172,172) #ACACAC srgb(172,172,172)
       173: (173,173,173) #ADADAD grey68
       174: (174,174,174) #AEAEAE srgb(174,174,174)
       175: (175,175,175) #AFAFAF srgb(175,175,175)
       176: (176,176,176) #B0B0B0 grey69
       177: (177,177,177) #B1B1B1 srgb(177,177,177)
       178: (178,178,178) #B2B2B2 srgb(178,178,178)
       179: (179,179,179) #B3B3B3 grey70
       180: (180,180,180) #B4B4B4 srgb(180,180,180)
       181: (181,181,181) #B5B5B5 grey71
       182: (182,182,182) #B6B6B6 srgb(182,182,182)
       183: (183,183,183) #B7B7B7 srgb(183,183,183)
       184: (184,184,184) #B8B8B8 grey72
       185: (185,185,185) #B9B9B9 srgb(185,185,185)
       186: (186,186,186) #BABABA grey73
       187: (187,187,187) #BBBBBB srgb(187,187,187)
       188: (188,188,188) #BCBCBC srgb(188,188,188)
       189: (189,189,189) #BDBDBD grey74
       190: (190,190,190) #BEBEBE grey
       191: (191,191,191) #BFBFBF grey75
       192: (192,192,192) #C0C0C0 silver
       193: (193,193,193) #C1C1C1 srgb(193,193,193)
       194: (194,194,194) #C2C2C2 grey76
       195: (195,195,195) #C3C3C3 srgb(195,195,195)
       196: (196,196,196) #C4C4C4 grey77
       197: (197,197,197) #C5C5C5 srgb(197,197,197)
       198: (198,198,198) #C6C6C6 srgb(198,198,198)
       199: (199,199,199) #C7C7C7 grey78
       200: (200,200,200) #C8C8C8 srgb(200,200,200)
       201: (201,201,201) #C9C9C9 grey79
       202: (202,202,202) #CACACA srgb(202,202,202)
       203: (203,203,203) #CBCBCB srgb(203,203,203)
       204: (204,204,204) #CCCCCC grey80
       205: (205,205,205) #CDCDCD srgb(205,205,205)
       206: (206,206,206) #CECECE srgb(206,206,206)
       207: (207,207,207) #CFCFCF grey81
       208: (208,208,208) #D0D0D0 srgb(208,208,208)
       209: (209,209,209) #D1D1D1 grey82
       210: (210,210,210) #D2D2D2 srgb(210,210,210)
       211: (211,211,211) #D3D3D3 LightGray
       212: (212,212,212) #D4D4D4 grey83
       213: (213,213,213) #D5D5D5 srgb(213,213,213)
       214: (214,214,214) #D6D6D6 grey84
       215: (215,215,215) #D7D7D7 srgb(215,215,215)
       216: (216,216,216) #D8D8D8 srgb(216,216,216)
       217: (217,217,217) #D9D9D9 grey85
       218: (218,218,218) #DADADA srgb(218,218,218)
       219: (219,219,219) #DBDBDB grey86
       220: (220,220,220) #DCDCDC gainsboro
       221: (221,221,221) #DDDDDD srgb(221,221,221)
       222: (222,222,222) #DEDEDE grey87
       223: (223,223,223) #DFDFDF srgb(223,223,223)
       224: (224,224,224) #E0E0E0 grey88
       225: (225,225,225) #E1E1E1 srgb(225,225,225)
       226: (226,226,226) #E2E2E2 srgb(226,226,226)
       227: (227,227,227) #E3E3E3 grey89
       228: (228,228,228) #E4E4E4 srgb(228,228,228)
       229: (229,229,229) #E5E5E5 grey90
       230: (230,230,230) #E6E6E6 srgb(230,230,230)
       231: (231,231,231) #E7E7E7 srgb(231,231,231)
       232: (232,232,232) #E8E8E8 grey91
       233: (233,233,233) #E9E9E9 srgb(233,233,233)
       234: (234,234,234) #EAEAEA srgb(234,234,234)
       235: (235,235,235) #EBEBEB grey92
       236: (236,236,236) #ECECEC srgb(236,236,236)
       237: (237,237,237) #EDEDED grey93
       238: (238,238,238) #EEEEEE srgb(238,238,238)
       239: (239,239,239) #EFEFEF srgb(239,239,239)
       240: (240,240,240) #F0F0F0 grey94
       241: (241,241,241) #F1F1F1 srgb(241,241,241)
       242: (242,242,242) #F2F2F2 grey95
       243: (243,243,243) #F3F3F3 srgb(243,243,243)
       244: (244,244,244) #F4F4F4 srgb(244,244,244)
       245: (245,245,245) #F5F5F5 grey96
       246: (246,246,246) #F6F6F6 srgb(246,246,246)
       247: (247,247,247) #F7F7F7 grey97
       248: (248,248,248) #F8F8F8 srgb(248,248,248)
       249: (249,249,249) #F9F9F9 srgb(249,249,249)
       250: (250,250,250) #FAFAFA grey98
       251: (251,251,251) #FBFBFB srgb(251,251,251)
       252: (252,252,252) #FCFCFC grey99
       253: (253,253,253) #FDFDFD srgb(253,253,253)
       254: (254,254,254) #FEFEFE srgb(254,254,254)
       255: (255,255,255) #FFFFFF white
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Interlace: None
  Background color: white
  Border color: srgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Compose: Over
  Page geometry: 128x128+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: Undefined
  Properties:
    date:create:
    date:modify:
    label: images/image.rgba
    signature:
  Artifacts:
    filename: image.rgba
    verbose: true
  Tainted: False
  Filesize: 33.3KB
  Number pixels: 16.4K
  Pixels per second: 16.384EB
  User time: 0.010u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.8.0-7 2012-11-30 Q16 http://www.imagemagick.org