diff options
Diffstat (limited to 'pnmtopng.html')
-rw-r--r-- | pnmtopng.html | 116 |
1 files changed, 68 insertions, 48 deletions
diff --git a/pnmtopng.html b/pnmtopng.html index b2c827f6..14888577 100644 --- a/pnmtopng.html +++ b/pnmtopng.html @@ -28,6 +28,7 @@ pnmtopng - convert a PNM image to PNG [<b>-rgb="</b><i>wx</i> <i>wy</i> <i>rx</i> <i>ry</i> <i>gx</i> <i>gy</i> <i>bx</i> <i>by</i><b>"</b>] [<b>-size="</b><i>x</i> <i>y</i> <i>unit</i><b>"</b>] +[<b>-srgbintent=</b><i>intent</i>] [<b>-modtime="</b>[<i>yy</i>]<i>yy</i><b>-</b><i>mm</i><b>-</b><i>dd</i> <i>hh</i><b>:</b><i>mm</i><b>:</b><i>ss</i><b>"</b>] [<b>-nofilter</b>] @@ -229,54 +230,6 @@ images from scratch do it with a gamma transfer in which the gamma value is <DD>Use this parameter to create a chunk that specifies the frequency (or histogram) of the colors in the image. -<DT><B>-rgb=</b><i>chroma_list</i> - -<DD>This option specifies how red, green, and blue component values -of a pixel specify a particular color, by telling the chromaticities -of those 3 primary illuminants and of white (i.e. full strength of -all three). - -<p>The <i>chroma_list</i> value is a blank-separated list of 8 floating -point decimal numbers. The CIE-1931 X and Y chromaticities (in that -order) of each of white, red, green, and blue, in that order. - -<p>This information goes into the PNG's cHRM chunk. - -<p>In a shell command, make sure you use quotation marks so that the -blanks in <i>chroma_list</i> don't make the shell see multiple command -arguments. - -<p>This option was new in Netpbm 10.30 (October 2005). Before that, -the option <b>-chroma</b> does the same thing, but with slightly -different syntax. - -<DT><B>-size="</b><i>x</i> <i>y</i> <i>unit</i><b>"</b> - -<DD>This option determines the aspect ratio of the individual pixels -of your image as well as the physical resolution of it. - -<p><i>unit</i> is either <b>0</b> or <i>1</i>. When it is <i>1</i>, -the option specifies the physical resolution of the image in pixels -per meter. For example, <b>-size="10000 15000 1"</b> means -that when someone displays the image, he should make it so that 10,000 -pixels horizontally occupy 1 meter and 15,000 pixels vertically occupy -one meter. And even if he doesn't take this advice on the overall -size of the displayed image, he should at least make it so that each -pixel displays as 1.5 times as high as wide. - -<p>When <i>unit</i> is <b>0</b>, that means there is no advice on -the absolute physical resolution; just on the ratio of horizontal to -vertical physical resolution. - -<p>This information goes into the PNG's pHYS chunk. - -<p>When you don't specify <b>-size</b>, <b>pnmtopng</b> creates the image -with no pHYS chunk, which means square pixels of no absolute resolution. - -<p>This option was new in Netpbm 10.30 (October 2005). Before that, -the option <b>-phys</b> does the same thing, but with slightly -different syntax. - <DT><B>-text=</b><i>filename</i> <DD> @@ -334,6 +287,73 @@ size of or number of lines in the file. <DD>The same as <b>-text</b>, except <b>pnmtopng</b> considers the text compressed. +<DT><B>-rgb=</b><i>chroma_list</i> + +<DD>This option specifies how red, green, and blue component values +of a pixel specify a particular color, by telling the chromaticities +of those 3 primary illuminants and of white (i.e. full strength of +all three). + +<p>The <i>chroma_list</i> value is a blank-separated list of 8 floating +point decimal numbers. The CIE-1931 X and Y chromaticities (in that +order) of each of white, red, green, and blue, in that order. + +<p>This information goes into the PNG's cHRM chunk. + +<p>In a shell command, make sure you use quotation marks so that the +blanks in <i>chroma_list</i> don't make the shell see multiple command +arguments. + +<p>This option was new in Netpbm 10.30 (October 2005). Before that, +the option <b>-chroma</b> does the same thing, but with slightly +different syntax. + +<DT><B>-size="</b><i>x</i> <i>y</i> <i>unit</i><b>"</b> + +<DD>This option determines the aspect ratio of the individual pixels +of your image as well as the physical resolution of it. + +<p><i>unit</i> is either <b>0</b> or <i>1</i>. When it is <i>1</i>, +the option specifies the physical resolution of the image in pixels +per meter. For example, <b>-size="10000 15000 1"</b> means +that when someone displays the image, he should make it so that 10,000 +pixels horizontally occupy 1 meter and 15,000 pixels vertically occupy +one meter. And even if he doesn't take this advice on the overall +size of the displayed image, he should at least make it so that each +pixel displays as 1.5 times as high as wide. + +<p>When <i>unit</i> is <b>0</b>, that means there is no advice on +the absolute physical resolution; just on the ratio of horizontal to +vertical physical resolution. + +<p>This information goes into the PNG's pHYS chunk. + +<p>When you don't specify <b>-size</b>, <b>pnmtopng</b> creates the image +with no pHYS chunk, which means square pixels of no absolute resolution. + +<p>This option was new in Netpbm 10.30 (October 2005). Before that, +the option <b>-phys</b> does the same thing, but with slightly +different syntax. + +<dt><b>-srgbintent=</b><i>intent</i> +<dd>This asserts that the input is a pseudo-Netpbm image that uses an +sRGB color space (unlike true Netpbm) and indicates how you intend for the +colors to be rendered. It causes <b>pamtopng</b> to include an sRGB chunk +in the PNG image that specifies that intent, so see the PNG documentation for +more information on what this really means. + +<p><i>intent</i> is one of: + +<ul> +<li><b>perceptual</b> +<li><b>relativecolorimetric</b> +<li><b>saturation</b> +<li><b>absolutecolorimetric</b> +</ul> + +<p>This option was new in Netpbm 10.71 (June 2015). Before that, +<b>pnmtopng</b> never generates an sRGB chunk. + <DT><B>-modtime="</b>[<i>yy</i>]<i>yy-mm-dd hh:mm:ss</i><b>"</b> <DD>This option allows you to specify the modification time value to |