Clarify and update rgbgfx documentation

Signed-off-by: obskyr <powpowd@gmail.com>
This commit is contained in:
obskyr
2018-02-15 15:05:52 +01:00
parent b8af100c63
commit 898f75ce57
2 changed files with 67 additions and 23 deletions

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@@ -43,7 +43,28 @@
</table>
<h1 class="Sh" title="Sh" id="DESCRIPTION"><a class="selflink" href="#DESCRIPTION">DESCRIPTION</a></h1>
The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
Nintendo Game Boy's planar tile format. The arguments are as follows:
Nintendo Game Boy's planar tile format.
<div style="height: 1.00em;">&#x00A0;</div>
The resulting colors and their palette indices are determined differently
depending on the input PNG file:
<ul class="Bl-dash">
<li class="It-dash">If the file has an embedded palette, that palette's color
and order are used.</li>
<li class="It-dash">If not, and the image only contains shades of gray, rgbgfx
maps them to the indices appropriate for each shade. Any undetermined
indices are set to respective default shades of gray. For example: if the
bit depth is 2 and the image contains light gray and black, they become
the second and fourth colors - and the first and third colors get set to
default white and dark gray. If the image has multiple shades that map to
the same index, the palette is instead determined as if the image had
color.</li>
<li class="It-dash">If the image has color (or the grayscale method failed),
the colors are sorted from lightest to darkest.</li>
</ul>
<div style="height: 1.00em;">&#x00A0;</div>
The input image may not contain more colors than the selected bit depth allows.
Transparent pixels are set to palette index 0.
<h1 class="Sh" title="Sh" id="ARGUMENTS"><a class="selflink" href="#ARGUMENTS">ARGUMENTS</a></h1>
<dl class="Bl-tag">
<dt class="It-tag">&#x00A0;</dt>
<dd class="It-tag">&#x00A0;</dd>
@@ -58,14 +79,14 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#F"><b class="Fl" title="Fl" id="F">-F</b></a></dt>
<dd class="It-tag">Same as <b class="Fl" title="Fl">-f</b>, but additionally,
the input PNG file is fixed to have its parameters match the command
line's parameters.</dd>
the supplied command line parameters are saved within the PNG and will be
loaded and automatically used next time.</dd>
<dt class="It-tag">&#x00A0;</dt>
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#d"><b class="Fl" title="Fl" id="d">-d</b></a>
<var class="Ar" title="Ar">depth</var></dt>
<dd class="It-tag">The bitdepth of the output image (either 1 or 2). By
default, the bitdepth is 2 (two bits per pixel).</dd>
<dd class="It-tag">The bit depth of the output image (either 1 or 2). By
default, the bit depth is 2 (two bits per pixel).</dd>
<dt class="It-tag">&#x00A0;</dt>
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#h"><b class="Fl" title="Fl" id="h">-h</b></a></dt>
@@ -79,15 +100,16 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#p"><b class="Fl" title="Fl" id="p">-p</b></a>
<var class="Ar" title="Ar">palfile</var></dt>
<dd class="It-tag">Raw bytes (8 bytes for two bits per pixel, 4 bytes for one
bit per pixel) containing the RGB15 values in the little-endian byte order
and then ordered from lightest to darkest.</dd>
<dd class="It-tag">Output the image's palette in standard GBC palette format -
bytes (8 bytes for two bits per pixel, 4 bytes for one bit per pixel)
containing the RGB15 values in little-endian byte order. If the palette
contains too few colors, the remaining entries are set to black.</dd>
<dt class="It-tag">&#x00A0;</dt>
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#P"><b class="Fl" title="Fl" id="P">-P</b></a></dt>
<dd class="It-tag">Same as <b class="Fl" title="Fl">-p</b>, but the pallete
file output name is made by taking the input filename, removing the file
extension, and appending <i class="Pa" title="Pa">.pal</i>.</dd>
<dd class="It-tag">Same as <b class="Fl" title="Fl">-p</b>, but the palette
file output name is made by taking the input PNG file's filename, removing
the file extension, and appending <i class="Pa" title="Pa">.pal</i>.</dd>
<dt class="It-tag">&#x00A0;</dt>
<dd class="It-tag">&#x00A0;</dd>
<dt class="It-tag"><a class="selflink" href="#t"><b class="Fl" title="Fl" id="t">-t</b></a>
@@ -120,7 +142,7 @@ The <b class="Nm" title="Nm">rgbgfx</b> program converts PNG images into the
<dd class="It-tag">Trim the end of the output file by this many tiles.</dd>
</dl>
<h1 class="Sh" title="Sh" id="EXAMPLES"><a class="selflink" href="#EXAMPLES">EXAMPLES</a></h1>
The following will take a PNG file with a bitdepth of 1, 2, or 8, and output
The following will take a PNG file with a bit depth of 1, 2, or 8, and output
planar 2bpp data:
<div class="Pp"></div>
<div class="D1">$ rgbgfx -o out.2bpp in.png</div>