Inconsistent HSB behaviour in Android and Standard modes?

Android Processing

zimady

Inconsistent HSB behaviour in Android and Standard modes?

in Android Processing • 1 year ago

I'm having some weird colour issues in an Android project I'm working on. Everything works fine in Standard mode but misbehaves in Android mode. Whilst trying to debug the issue, I realised that HSB colorMode behaves differently in Android mode than Standard mode.

I've condensed the issue into a small sketch. The comments describe exactly the problem and how to duplicate it. If anyone can offer an explanation for the color inconsistencies between Android and Standard modes, it may help me to identify the issue in my sketch.

Thanks.

[EDIT] I discovered another clue. The colour change seen in case 4 in the sketch is *always* the same. i.e. it doesn't seem to matter what rgbColor is set to, it will be rendered pink if the HSB conversion is done.

/*
* Inconsistent HSB behaviour in STANDARD & ANDROID modes?
* To replicate:
*
* Compile in STANDARD mode
* 1) set useRGB = true. Compile. Note colours (screen grab if necessary)
* 2) set useRGB = false. Compile. Note colours are the same (compare screen grab if necessary)
*
* Compile in ANDROID mode
* 3) set useRGB = true. Compile. Note colours (screen grab if necessary)
* 4) set useRGB = false. Compile. Note colours are DIFFERENT!! (compare screenshot if necessary)
*/
color backgroundColor = #231000;
color rgbColor = #66ffff;
color fillColor;
boolean useRGB = false;
void setup() {
//size( 500, 500 ); // use for STANDARD compiler
noStroke();
}
void draw() {
background( backgroundColor );
rectMode(CENTER);
translate( width/2, height/2 );
if( useRGB ) {
fillColor = rgbColor;
} else {
// all we do when useRGB == false is change colorMode to HSB, grab HSB components,
// recreate colour, revert colorMode back to RGB
colorMode( HSB, 255 );
float h = hue( rgbColor );
float s = saturation( rgbColor );
float b = brightness( rgbColor );
fillColor = color(h, s, b);
colorMode( RGB, 255 );
}
fill( fillColor );
rect( 0, 0, 200, 200 );
}

Replies(3)

zimady

Re: Inconsistent HSB behaviour in Android and Standard modes?

1 year ago

I found the cause (which I believe is a bug) and a workaround.

If I print out the values that I get from hue(), saturation() and brightness() in Android mode, I get some odd values for hue - for example:

FF447E > 87054.55, 187.0, 255.0

7EF345 > 25587.932, 182.59259, 243.0

66ffff > 45900.0, 153.0, 255.0

Given that, according to the documentation, colorMode( HSB, 255 ) supposedly sets the range to 255, the returned values for hue are clearly incorrect. I haven't tried to figure out the relationship those incorrect values have to the colour values going in (I'm guessing there is one).

Instead, when I realised the issues, I abandoned Processing's native methods and looked to native Android classes, specifically, android.graphics.Color which includes some handy colour conversion methods. In case it's useful to others, the working code is included below.

[EDIT] Bug report submitted: http://code.google.com/p/processing/issues/detail?id=1257

import android.graphics.Color;
color backgroundColor = #231000;
color rgbColor = #66ffff;
color fillColor;
boolean useRGB = false;
void setup() {
//size( 500, 500 ); // use for STANDARD compiler
noStroke();
}
void draw() {
background( backgroundColor );
rectMode(CENTER);
translate( width/2, height/2 );
if( useRGB ) {
fillColor = rgbColor;
} else {
// wil be used for workaround
int re = round(red(rgbColor));
int gr = round(green(rgbColor));
int bl = round(blue(rgbColor));
colorMode( HSB, 255 );
float h = hue( rgbColor );
float s = saturation( rgbColor );
float b = brightness( rgbColor );
// note the odd value for hue we got (in Android mode)
println( Float.toString(h) + ", " + Float.toString(s) + ", " + Float.toString(b) );
// here begins the workaround using native Android Color class
float[] hsv = new float[3];
Color.RGBToHSV( re, gr, bl, hsv);
h = hsv[0];
s = hsv[1];
b = hsv[2];
// convert to values like we'd get in Standard mode
h = (h/float(360))*255;
s = s * 255;
b = s * 255;
// here begins the workaround
// in my implementation, I do some tranformations to the h, s, b values here (it isn't pointless conversion!)
fillColor = color(h, s, b);
colorMode( RGB, 255 );
}
fill( fillColor );
rect( 0, 0, 200, 200 );
}

calsign

Re: Inconsistent HSB behaviour in Android and Standard modes?

1 year ago

Wow. I came across this error several times but lacked the desire and perseverance to isolate it. I see that it is a bug... congratulations! I think you should report a bug.

zimady

Re: Inconsistent HSB behaviour in Android and Standard modes?

1 year ago

Hey calsign, thanks for the suggestion. I think I reported the bug just as you were replying.

As for desire and perseverance: I lacked the former but had the latter. I have a Masters degree show opening in 2 days and my project relies heavily on being able to transform colours in HSB/HSV mode. I had no choice but find a solution :)

I hope the work saves someone else several late nights of panic, blood, sweat and tears!!