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PierreRaybautPierreRaybaut
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Add new step alpha function
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Lines changed: 212 additions & 149 deletions

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‎CHANGELOG.md‎

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@@ -2,7 +2,18 @@
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## Version 2.1.2 ##
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5-
Compatibility with PythonQwt 0.12.
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New features:
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* Added `Echelon` alpha function to the image parameters:
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* The `Echelon` alpha function is a step function, so that the alpha channel is
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0 (full transparency) for the lowest value of the Lookup Table (LUT) and opaque
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(transparency level set by the `Global alpha` parameter) for the other values
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* This feature is added to the other existing alpha functions: `Constant`, `Linear`,
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`Sigmoid`, and `Hyperbolic tangent`
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Bug fixes:
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* Compatibility with PythonQwt 0.12.
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## Version 2.1.1 ##
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‎doc/dev/guiqwt_to_plotpy.rst‎

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@@ -189,6 +189,7 @@ functions are:
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* :py:attr:`plotpy.constants.LUTAlpha.LINEAR`
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* :py:attr:`plotpy.constants.LUTAlpha.SIGMOID`
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* :py:attr:`plotpy.constants.LUTAlpha.TANH`
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* :py:attr:`plotpy.constants.LUTAlpha.STEP`
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.. warning:: The ``alpha_mask`` parameter has been removed from the methods
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:py:meth:`.PlotBuilder.image`, :py:meth:`.PlotBuilder.xyimage`,

‎doc/dev/v1_to_v2.rst‎

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@@ -77,6 +77,7 @@ functions are:
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* :py:attr:`plotpy.constants.LUTAlpha.LINEAR`
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* :py:attr:`plotpy.constants.LUTAlpha.SIGMOID`
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* :py:attr:`plotpy.constants.LUTAlpha.TANH`
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* :py:attr:`plotpy.constants.LUTAlpha.STEP`
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.. warning:: The ``alpha_mask`` parameter has been removed from the methods
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:py:meth:`.PlotBuilder.image`, :py:meth:`.PlotBuilder.xyimage`,

‎plotpy/builder/image.py‎

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@@ -168,8 +168,8 @@ def image(
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filename: image filename. Default is None
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is None
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background_color: background color name. Default is None
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colormap: colormap name. Default is None
@@ -317,8 +317,8 @@ def maskedimage(
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filename: image filename. Default is None
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
320-
Default is :py:attr:`.LUTAlpha.NONE`
321-
(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is 1.0
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xdata: x data. Default is [None, None]
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ydata: y data. Default is [None, None]
@@ -445,8 +445,8 @@ def maskedxyimage(
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mask: mask. Default is None
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is 1.0
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background_color: background color. Default is None
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colormap: colormap. Default is None
@@ -519,8 +519,8 @@ def rgbimage(
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filename: filename. Default is None
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is 1.0
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xdata: x data. Default is [None, None]
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ydata: y data. Default is [None, None]
@@ -584,8 +584,8 @@ def quadgrid(
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Z: data
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is None
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colormap: colormap. Default is None
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interpolation: interpolation method. Default is 'linear'
@@ -662,8 +662,8 @@ def trimage(
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filename: filename. Default is None
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is None
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background_color: background color. Default is None
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colormap: colormap. Default is None
@@ -743,8 +743,8 @@ def xyimage(
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data: data
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title: image title. Default is None
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alpha_function: function for LUT alpha channel.
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Default is :py:attr:`.LUTAlpha.NONE`
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(valid string values are 'none', 'constant', 'linear', 'sigmoid', 'tanh')
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Default is :py:attr:`.LUTAlpha.NONE` (valid string values are 'none',
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'constant', 'linear', 'sigmoid', 'tanh' and 'step')
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alpha: alpha value. Default is None
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background_color: background color. Default is None
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colormap: colormap. Default is None

‎plotpy/constants.py‎

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@@ -102,6 +102,9 @@ class LUTAlpha(enum.Enum):
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#: Hyperbolic tangent alpha function
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TANH = 4
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#: Transparent lowest value and opaque highest value
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STEP = 5
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@classmethod
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def get_member_from_name(cls: type["LUTAlpha"], name: str) -> "LUTAlpha|None":
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"""Return the member of the enum from its name"""
@@ -110,16 +113,34 @@ def get_member_from_name(cls: type["LUTAlpha"], name: str) -> "LUTAlpha|None":
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return member
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return None
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def get_choices(self):
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@classmethod
117+
def get_choices(cls: type["LUTAlpha"]) -> list[tuple[int, str]]:
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"""Return the list of choices"""
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return [
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(LUTAlpha.NONE.value, _("None")),
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(LUTAlpha.CONSTANT.value, _("Constant")),
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(LUTAlpha.LINEAR.value, _("Linear")),
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(LUTAlpha.SIGMOID.value, _("Sigmoid")),
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(LUTAlpha.TANH.value, _("Hyperbolic tangent")),
125+
(LUTAlpha.STEP.value, _("Step")),
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]
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128+
@classmethod
129+
def get_help(cls: type["LUTAlpha"]) -> str:
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"""Return tooltip help for all alpha functions"""
131+
return _(
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"Alpha function applied to the Look-Up Table (LUT)<br>"
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"to control the transparency of the image:<br>"
134+
"(maximum opacity is given by the <b>Global alpha</b> parameter)<br><br>"
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"<b>None</b>: No alpha function<br>"
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"<b>Constant</b>: Constant alpha function<br>"
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"<b>Linear</b>: Linear alpha function<br>"
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"<b>Sigmoid</b>: Sigmoid alpha function<br>"
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"<b>Hyperbolic tangent</b>: Hyperbolic tangent alpha function<br>"
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"<b>Step</b>: Lowest value of the LUT is 100% transparent, other "
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"values are opaque"
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)
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# Lookup table size
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LUT_SIZE = 1024

‎plotpy/items/image/base.py‎

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@@ -442,11 +442,17 @@ def set_color_map(self, name_or_table: str | EditableColormap) -> None:
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else:
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x = i / float(LUT_SIZE - 1)
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if alpha_function == LUTAlpha.LINEAR.value:
445+
# Linear alpha function
445446
pix_alpha = alpha * x
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elif alpha_function == LUTAlpha.SIGMOID.value:
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# Sigmoid alpha function
447449
pix_alpha = alpha / (1 + np.exp(-10 * x))
448450
elif alpha_function == LUTAlpha.TANH.value:
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# Hyperbolic tangent alpha function
449452
pix_alpha = alpha * np.tanh(5 * x)
453+
elif alpha_function == LUTAlpha.STEP.value:
454+
# Fully transparent lowest value and `alpha` transparent elsewhere
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pix_alpha = alpha if x > 0 else 0
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else:
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raise ValueError(f"Invalid alpha function {alpha_function}")
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# pylint: disable=too-many-function-args
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def serialize(
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self,
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writer: guidata.dataset.io.HDF5Writer
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| guidata.dataset.io.INIWriter
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| guidata.dataset.io.JSONWriter,
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writer: (
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guidata.dataset.io.HDF5Writer
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| guidata.dataset.io.INIWriter
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| guidata.dataset.io.JSONWriter
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),
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) -> None:
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"""Serialize object to HDF5 writer
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12431251
def deserialize(
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self,
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reader: guidata.dataset.io.HDF5Reader
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| guidata.dataset.io.INIReader
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| guidata.dataset.io.JSONReader,
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reader: (
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guidata.dataset.io.HDF5Reader
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| guidata.dataset.io.INIReader
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| guidata.dataset.io.JSONReader
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),
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) -> None:
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"""Deserialize object from HDF5 reader
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‎plotpy/locale/fr/LC_MESSAGES/plotpy.mo‎

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