File talk:Roundel of the USAF.svg

Hello, I posted a modification to ZScout370's file. I modified the width of the image--previous version had bars "attached" at horizontal centerline of circle (final image width 2040), but per specification bars should be "attached" and dimensioned from the top of horizontal extension of the star. The adjusted image width is now 1993.0143 wide. I left the file width at 2040. The colors remain the same. The base circle, inscribed star, remain border dimensions remain the same.

EXPLANATION Per Department of Defense and Air Force Technical Orders (see documents listed in "Source" to include File:[[1]] ), the image is dimensioned from the radius of the base circle [ RAD = r ]. All other dimensions must be calculated from the ratios and dimensioning on the specification. The bar is one radius long / wide [ r ]. The red portion is one-sixth radius tall / high [ (1/6)r ]; the composite bar is one-half radius tall, thus each white portion is also one-sixth's radius tall / high [ (3/6)r = (1/2)r ]. All portions have a border measuring one-eighth the radius [ (1/8)r ].

Dimensioning the bar from the star (as opposed to the circle) has an effect of reducing the width by [ cosine(90 - 72) = cos(18) = 0.9511 ] of the base radius (base radius = 480 pixels in this graphic) which is a reduction of 46.9857 pixels on each side.

IMAGE HEIGHT: height is the border height on top/bottom and double the radius of basic circle (r); constructing from top to bottom yields: height = border height + basic circle radius + basic circle radius + border height height = (1/8)r + r + r + (1/8)r = 2.25r height = 60 + 480 + 480 + 60 = 1080 (for base circle radius 480 pixels)

IMAGE WIDTH (corrected): width is the border width on each side, the bar width on each side, and the star width on each side (not the circle width on each side)*; constructing from side to side yields: width = border width + bar width + star width across the horizontal + bar width + border width width = (1/8)r + r + cos(90 - 72)r + cos(90 - 72)r + r + (1/8)r = 4.1521r width = 1993.0143 pixels (for base circle radius 480 pixels)

   see [[2]] which shows |<--- RAD --->| dimensioning from horizontal vertex of star

IMAGE WIDTH (previous) Previous version had bar extending one radius from the center of the basic circle. width = border width + bar width + basic circle diameter + bar width + border width width = 1/8r + r + r + r + r + 1/8r = 4.25r = 2040 pixels (for base circle radius 480 pixels)

NOTE: I was uncertain as to crop the new image (final image size 1080 x 1993.0143) or round the width to an even 1994 pixels. I decided to leave the file width the same size and to not do any rounding. --SistineKid (talk) 22:46, 25 January 2014 (UTC)