a ߙfbR@sFdZddlZddlmZddlmZgdZd,ddZd-d d ZGd d d eZ Gddde Z Gddde Z Gddde Z Gddde Z Gddde ZGddde ZGddde ZGddde ZGddde ZGd d!d!e ZGd"d#d#e ZGd$d%d%e ZGd&d'd'e ZGd(d)d)e ZGd*d+d+ee ZdS).z Classes that deal with stretching, i.e. mapping a range of [0:1] values onto another set of [0:1] values with a transformation N) BaseTransform)CompositeTransform) BaseStretch LinearStretch SqrtStretch PowerStretchPowerDistStretchSquaredStretch LogStretch AsinhStretch SinhStretch HistEqStretchContrastBiasStretchCompositeStretchcCsH|durt|t|Stj||dtj|t||d|SdS)zCalculate the log base n of x.Nout)nplog true_divide)nxrr 0)r0r1 ValueErrorpowerr"ar4rrr1s zPowerStretch.__init__TNcCst|||d}| oN|duoNd|jko0dknpNd|jkoJdkn}tjdd.|rj|dk}tj||j|dWdn1s0Y|r|||<|S) r=r6Nrrr>r?r)r rGrrArBrrrr(s0zPowerStretch.__call__cCstd|jSr9)rrGr!rrrr*szPowerStretch.inverse)TNN r+r,r-r.r/r#r1r(r*r;rrr4rrs   .rcs8eZdZdZd fdd Zd ddZed d ZZS) r aI An alternative power stretch. The stretch is given by: .. math:: y = \frac{a^x - 1}{a - 1} Parameters ---------- a : float, optional The ``a`` parameter used in the above formula. ``a`` must be greater than or equal to 0, but cannot be set to 1. Default is 1000. @@cs,|dks|dkrtdt||_dSNrrz&a must be >= 0, but cannot be set to 1rFr0r1exprHr4rrr1s zPowerDistStretch.__init__TNcCsJt|||d}tj|j||dtj|d|dtj||jd|d|S)Nr6rrr)r rrGrOsubtractrr'rrrr(!s zPowerDistStretch.__call__cCs t|jdSr)rI)InvertedPowerDistStretchrOr!rrrr*(szPowerDistStretch.inverse)rL)TNr:rrr4rr s  r cs8eZdZdZd fdd Zd ddZed d ZZS) rSa Inverse transformation for `~astropy.image.scaling.PowerDistStretch`. The stretch is given by: .. math:: y = \frac{\log(y (a-1) + 1)}{\log a} Parameters ---------- a : float, optional The ``a`` parameter used in the above formula. ``a`` must be greater than or equal to 0, but cannot be set to 1. Default is 1000. rLcs,|dks|dkrtdt||_dSrMrNrHr4rrr1@s z!InvertedPowerDistStretch.__init__TNcCsHt|||d}tj||jd|dtj|d|dt|j||d|S)Nr6rrr)r rr7rOr8rr'rrrr(Fs z!InvertedPowerDistStretch.__call__cCs t|jdSrQ)r rOr!rrrr*Msz InvertedPowerDistStretch.inverse)rL)TNr:rrr4rrS.s  rScs,eZdZdZfddZeddZZS)r zt A convenience class for a power stretch of 2. The stretch is given by: .. math:: y = x^2 cstddS)NrD)r0r1r!r4rrr1]szSquaredStretch.__init__cCstSr))rr!rrrr*`szSquaredStretch.inverse)r+r,r-r.r1r/r*r;rrr4rr Ss r csDeZdZdZeddZd fdd Zdd d Zed d ZZ S)r a A log stretch. The stretch is given by: .. math:: y = \frac{\log{(a x + 1)}}{\log{(a + 1)}} Parameters ---------- a : float The ``a`` parameter used in the above formula. ``a`` must be greater than 0. Default is 1000. cCsdSr<rr!rrrr#vszLogStretch._supports_invalid_kwrLcs$t|dkrtd||_dSrEr0r1rFrOrHr4rrr1zs zLogStretch.__init__TNcCst|||d}| o|du}tjddh|r6|dk}tj||j|dtj|d|dtj||dtj|t|jd|dWdn1s0Y|r|||<|S)r=r6Nr>r?rrr)r rrAr7rOr8rrrBrrrr(s:zLogStretch.__call__cCs t|jSrT)InvertedLogStretchrOr!rrrr*szLogStretch.inverse)rL)TNNrKrrr4rr fs  /r cs6eZdZdZfddZd ddZedd ZZS) rVat Inverse transformation for `~astropy.image.scaling.LogStretch`. The stretch is given by: .. math:: y = \frac{e^{y \log{a + 1}} - 1}{a} \\ y = \frac{e^{y} (a + 1) - 1}{a} Parameters ---------- a : float, optional The ``a`` parameter used in the above formula. ``a`` must be greater than 0. Default is 1000. cs$t|dkrtd||_dSrErUrHr4rrr1s zInvertedLogStretch.__init__TNcCs^t|||d}tj|t|jd|dtj||dtj|d|dtj||j|d|S)Nr6rr)r rr7rrOrPrr'rrrr(s zInvertedLogStretch.__call__cCs t|jSrT)r rOr!rrrr*szInvertedLogStretch.inverse)TNr:rrr4rrVs   rVcs8eZdZdZd fdd Zd ddZed d ZZS) r a An asinh stretch. The stretch is given by: .. math:: y = \frac{{\rm asinh}(x / a)}{{\rm asinh}(1 / a)}. Parameters ---------- a : float, optional The ``a`` parameter used in the above formula. The value of this parameter is where the asinh curve transitions from linear to logarithmic behavior, expressed as a fraction of the normalized image. ``a`` must be greater than 0 and less than or equal to 1 (0 < a <= 1). Default is 0.1. 皙?cs,t|dks|dkr"td||_dSNrrza must be > 0 and <= 1r0r1rFrIrHr4rrr1s zAsinhStretch.__init__TNcCsNt|||d}tj||j|dtj||dtj|td|j|d|SNr6rr)r rrrIarcsinhr'rrrr(s zAsinhStretch.__call__cCstdtd|jdSr)rrR)r rr[rIr!rrrr*szAsinhStretch.inverse)rW)TNr:rrr4rr s  r cs8eZdZdZd fdd Zd ddZed d ZZS) r aT A sinh stretch. The stretch is given by: .. math:: y = \frac{{\rm sinh}(x / a)}{{\rm sinh}(1 / a)} Parameters ---------- a : float, optional The ``a`` parameter used in the above formula. ``a`` must be greater than 0 and less than or equal to 1 (0 < a <= 1). Default is 1/3. UUUUUU?cs,t|dks|dkr"td||_dSrXrYrHr4rrr1s zSinhStretch.__init__TNcCsNt|||d}tj||j|dtj||dtj|td|j|d|SrZ)r rrrIsinhr'rrrr(s zSinhStretch.__call__cCstdtd|jdSr\)r rr^rIr!rrrr*szSinhStretch.inverse)r])TNr:rrr4rr s  r c@s0eZdZdZd ddZd ddZedd ZdS) ra  A histogram equalization stretch. Parameters ---------- data : array-like The data defining the equalization. values : array-like, optional The input image values, which should already be normalized to the [0:1] range. NcCsvt||_|jt|j|_|j}|j}|j||||_|durltddt|j|_ n||_ dSNrr) rsortZraveldataisfiniteminmaxlinspacelenr)r"rarZvminZvmaxrrrr11s  zHistEqStretch.__init__TcCs,t|||d}t||j|j|dd<|SNr6)r rinterprarr'rrrr(?szHistEqStretch.__call__cCst|j|jdSr))r)InvertedHistEqStretchrarr!rrrr*DszHistEqStretch.inverse)N)TNr+r,r-r.r1r(r/r*rrrrr$s   rc@s0eZdZdZd ddZd ddZedd ZdS) rja. Inverse transformation for `~astropy.image.scaling.HistEqStretch`. Parameters ---------- data : array-like The data defining the equalization. values : array-like, optional The input image values, which should already be normalized to the [0:1] range. NcCs:|t||_|dur0tddt|j|_n||_dSr_)rrbrarerfr)r"rarrrrr1WszInvertedHistEqStretch.__init__TcCs,t|||d}t||j|j|dd<|Srg)r rrhrrar'rrrr(^szInvertedHistEqStretch.__call__cCst|j|jdSri)rrarr!rrrr*cszInvertedHistEqStretch.inverse)N)TNrkrrrrrjJs   rjcs6eZdZdZfddZd ddZedd ZZS) ra A stretch that takes into account contrast and bias. The stretch is given by: .. math:: y = (x - {\rm bias}) * {\rm contrast} + 0.5 and the output values are clipped to the [0:1] range. Parameters ---------- contrast : float The contrast parameter (see the above formula). bias : float The bias parameter (see the above formula). cst||_||_dSr$r0r1contrastbiasr"rmrnr4rrr1}s zContrastBiasStretch.__init__TNcCs\t|d|d}tj||j|dtj||j|dtj|d|d|rXtj|dd|d|S)NFr6r?rr)r rrPrnr7rmr8rr'rrrr(szContrastBiasStretch.__call__cCst|j|jSrT)InvertedContrastBiasStretchrmrnr!rrrr*szContrastBiasStretch.inverse)TNr:rrr4rris   rcs6eZdZdZfddZd ddZedd ZZS) rqa1 Inverse transformation for ContrastBiasStretch. Parameters ---------- contrast : float The contrast parameter (see `~astropy.visualization.ConstrastBiasStretch). bias : float The bias parameter (see `~astropy.visualization.ConstrastBiasStretch). cst||_||_dSr$rlror4rrr1s z$InvertedContrastBiasStretch.__init__TNcCs\t|d|d}tj|d|dtj||j|dtj||j|d|rXtj|dd|d|S)NFr6rprrr)r rrPrrmr8rnrr'rrrr(sz$InvertedContrastBiasStretch.__call__cCst|j|jSrT)rrmrnr!rrrr*sz#InvertedContrastBiasStretch.inverse)TNr:rrr4rrqs   rqc@seZdZdZdddZdS)ra A combination of two stretches. Parameters ---------- stretch_1 : :class:`astropy.visualization.BaseStretch` The first stretch to apply. stretch_2 : :class:`astropy.visualization.BaseStretch` The second stretch to apply. TNcCs|j|j|||d||dSrg)Z transform_2Z transform_1r'rrrr(szCompositeStretch.__call__)TN)r+r,r-r.r(rrrrrs r)N)TN)r.ZnumpyrZ transformrr__all__rr rrrrr rSr r rVr r rrjrrqrrrrrs,   )$@N$%O%&$&-'