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Color Image Conversion

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Mike Hales

Color Image Conversion

Is there an easy way to take a color image and convert it to a
grayscale image? Or even better, to take an OpaqueImage, and convert
it to an OpaqueImageWithEnablement with the disabled figure the
grayscale version of the enabled figure?

Thanks,

Mike

Travis Griggs-3

Re: Color Image Conversion

On Apr 27, 2007, at 21:17, Mike Hales wrote:

Is there an easy way to take a color image and convert it to a grayscale image? Or even better, to take an OpaqueImage, and convert it to an OpaqueImageWithEnablement with the disabled figure the grayscale version of the enabled figure?

How 'bout this?

OpaqueImage>>withEnablement: anEnablement

| gray |

gray := CachedImage on: (Image

extent: figure asImage extent

depth: 1

bitsPerPixel: 1

palette: (MappedPalette with: SymbolicPaint inactiveForeground asColorValue)).

^(OpaqueImageWithEnablement

figure: figure

shape: shape

inactiveFigure: gray

inactiveShape: shape) isEnabled: anEnablement

To test/play with it, I inspected:

(ListIconLibrary visualFor: #class) withEnablement: [InputState default shiftDown]

Then I could just refresh the inspector, if I hold the shift key, I see the normal, otherwise, I see the grayscale.

Is that what you were looking for?

Travis Griggs

Objologist

"Only one thing is impossible for God: to find any sense in any copyright law on the planet." - Mark Twain

Travis Griggs-3

Re: Color Image Conversion

In reply to this post by Mike Hales

On Apr 27, 2007, at 21:17, Mike Hales wrote:

Is there an easy way to take a color image and convert it to a grayscale image? Or even better, to take an OpaqueImage, and convert it to an OpaqueImageWithEnablement with the disabled figure the grayscale version of the enabled figure?

Or perhaps, on reflection (pun?), you really meant grayscale when you said grayscale. :)

Here's a version that does that. The exact algorithm to use in the paintTransfer block is yours to derive. You could use brightness, saturation, luminance, etc. I found 1 - saturation to be appealing for that particular icon. Luminance a second.

Please note that if your original figure is a 32bpp Image and has nonzero values in the X byte (i.e. you grabbed it from a Screen capture of a desktop that does transparency like the Mac), you will have issues with the convert. Load FixedPaletteFixed from the OR to get around it.

OpaqueImage>>prettyEnablement: anEnablement

| gray |

gray := CachedImage on: (figure asImage

convertToPalette: (MappedPalette

withColors: ((0 to: 255) collect: [:n | ColorValue brightness: n / 255]))

renderedBy: NearestPaint new

paintTransfer: [:color | ColorValue brightness: 1 - color saturation]).

^(OpaqueImageWithEnablement

figure: figure

shape: shape

inactiveFigure: gray

inactiveShape: shape) isEnabled: anEnablement

Travis Griggs

Objologist

"You A students, you'll be back soon teaching here with me. You B students, you'll actually go on to be real engineers. You C students, you'll go into management and tell the A and B students what to do." - My Fluid Dynamics Professor whom I have yet to disprove

Mike Hales

Re: Color Image Conversion

Perfect! Thanks at ton. I'll see you on Monday.

Mike

On Apr 28, 2007, at 4:36 AM, Travis Griggs wrote:

On Apr 27, 2007, at 21:17, Mike Hales wrote:

Is there an easy way to take a color image and convert it to a grayscale image? Or even better, to take an OpaqueImage, and convert it to an OpaqueImageWithEnablement with the disabled figure the grayscale version of the enabled figure?

Or perhaps, on reflection (pun?), you really meant grayscale when you said grayscale. :)

Here's a version that does that. The exact algorithm to use in the paintTransfer block is yours to derive. You could use brightness, saturation, luminance, etc. I found 1 - saturation to be appealing for that particular icon. Luminance a second.

Please note that if your original figure is a 32bpp Image and has nonzero values in the X byte (i.e. you grabbed it from a Screen capture of a desktop that does transparency like the Mac), you will have issues with the convert. Load FixedPaletteFixed from the OR to get around it.

OpaqueImage>>prettyEnablement: anEnablement
| gray |
gray := CachedImage on: (figure asImage
convertToPalette: (MappedPalette
withColors: ((0 to: 255) collect: [:n | ColorValue brightness: n / 255]))
renderedBy: NearestPaint new
paintTransfer: [:color | ColorValue brightness: 1 - color saturation]).
^(OpaqueImageWithEnablement
figure: figure
shape: shape
inactiveFigure: gray
inactiveShape: shape) isEnabled: anEnablement

--
Travis Griggs
Objologist
"You A students, you'll be back soon teaching here with me. You B students, you'll actually go on to be real engineers. You C students, you'll go into management and tell the A and B students what to do." - My Fluid Dynamics Professor whom I have yet to disprove