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@@ -20,6 +20,7 b' Authors:' | |||
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20 | 20 | from __future__ import print_function |
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21 | 21 | |
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22 | 22 | import os |
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23 | import struct | |
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23 | 24 | |
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24 | 25 | from IPython.utils.py3compat import string_types |
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25 | 26 | |
@@ -471,6 +472,32 b' class Javascript(DisplayObject):' | |||
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471 | 472 | _PNG = b'\x89PNG\r\n\x1a\n' |
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472 | 473 | _JPEG = b'\xff\xd8' |
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473 | 474 | |
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475 | def _pngxy(data): | |
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476 | """read the (width, height) from a PNG header""" | |
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477 | ihdr = data.index(b'IHDR') | |
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478 | # next 8 bytes are width/height | |
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479 | w4h4 = data[ihdr+4:ihdr+12] | |
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480 | return struct.unpack('>ii', w4h4) | |
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481 | ||
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482 | def _jpegxy(data): | |
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483 | """read the (width, height) from a JPEG header""" | |
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484 | # adapted from http://www.64lines.com/jpeg-width-height | |
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485 | ||
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486 | idx = 4 | |
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487 | while True: | |
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488 | block_size = struct.unpack('>H', data[idx:idx+2])[0] | |
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489 | idx = idx + block_size | |
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490 | if data[idx:idx+2] == b'\xFF\xC0': | |
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491 | # found Start of Frame | |
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492 | iSOF = idx | |
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493 | break | |
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494 | else: | |
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495 | # read another block | |
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496 | idx += 2 | |
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497 | ||
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498 | h, w = struct.unpack('>HH', data[iSOF+5:iSOF+9]) | |
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499 | return w, h | |
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500 | ||
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474 | 501 | class Image(DisplayObject): |
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475 | 502 | |
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476 | 503 | _read_flags = 'rb' |
@@ -478,7 +505,7 b' class Image(DisplayObject):' | |||
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478 | 505 | _FMT_PNG = u'png' |
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479 | 506 | _ACCEPTABLE_EMBEDDINGS = [_FMT_JPEG, _FMT_PNG] |
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480 | 507 | |
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481 | def __init__(self, data=None, url=None, filename=None, format=u'png', embed=None, width=None, height=None): | |
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508 | def __init__(self, data=None, url=None, filename=None, format=u'png', embed=None, width=None, height=None, retina=False): | |
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482 | 509 | """Create a display an PNG/JPEG image given raw data. |
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483 | 510 | |
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484 | 511 | When this object is returned by an expression or passed to the |
@@ -512,6 +539,13 b' class Image(DisplayObject):' | |||
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512 | 539 | Width to which to constrain the image in html |
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513 | 540 | height : int |
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514 | 541 | Height to which to constrain the image in html |
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542 | retina : bool | |
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543 | Automatically set the width and height to half of the measured | |
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544 | width and height. | |
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545 | This only works for embedded images because it reads the width/height | |
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546 | from image data. | |
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547 | For non-embedded images, you can just set the desired display width | |
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548 | and height directly. | |
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515 | 549 | |
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516 | 550 | Examples |
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517 | 551 | -------- |
@@ -561,12 +595,32 b' class Image(DisplayObject):' | |||
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561 | 595 | raise ValueError("Cannot embed the '%s' image format" % (self.format)) |
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562 | 596 | self.width = width |
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563 | 597 | self.height = height |
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598 | self.retina = retina | |
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564 | 599 | super(Image, self).__init__(data=data, url=url, filename=filename) |
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565 | 600 | |
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601 | if retina: | |
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602 | self._retina_shape() | |
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603 | ||
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604 | def _retina_shape(self): | |
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605 | """load pixel-doubled width and height from image data""" | |
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606 | if not self.embed: | |
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607 | return | |
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608 | if self.format == 'png': | |
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609 | w, h = _pngxy(self.data) | |
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610 | elif self.format == 'jpeg': | |
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611 | w, h = _jpegxy(self.data) | |
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612 | else: | |
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613 | # retina only supports png | |
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614 | return | |
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615 | self.width = w // 2 | |
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616 | self.height = h // 2 | |
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617 | ||
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566 | 618 | def reload(self): |
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567 | 619 | """Reload the raw data from file or URL.""" |
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568 | 620 | if self.embed: |
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569 | 621 | super(Image,self).reload() |
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622 | if self.retina: | |
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623 | self._retina_shape() | |
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570 | 624 | |
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571 | 625 | def _repr_html_(self): |
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572 | 626 | if not self.embed: |
@@ -9,7 +9,7 b' Authors' | |||
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9 | 9 | """ |
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10 | 10 | |
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11 | 11 | #----------------------------------------------------------------------------- |
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12 |
# Copyright (C) 2009 |
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12 | # Copyright (C) 2009 The IPython Development Team | |
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13 | 13 | # |
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14 | 14 | # Distributed under the terms of the BSD License. The full license is in |
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15 | 15 | # the file COPYING, distributed as part of this software. |
@@ -19,10 +19,10 b' Authors' | |||
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19 | 19 | # Imports |
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20 | 20 | #----------------------------------------------------------------------------- |
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21 | 21 | |
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22 | import struct | |
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23 | 22 | import sys |
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24 | 23 | from io import BytesIO |
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25 | 24 | |
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25 | from IPython.core.display import _pngxy | |
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26 | 26 | from IPython.utils.decorators import flag_calls |
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27 | 27 | |
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28 | 28 | # If user specifies a GUI, that dictates the backend, otherwise we read the |
@@ -103,22 +103,16 b" def print_figure(fig, fmt='png'):" | |||
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103 | 103 | dpi = rcParams['savefig.dpi'] |
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104 | 104 | if fmt == 'retina': |
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105 | 105 | dpi = dpi * 2 |
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106 | fmt = 'png' | |
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106 | 107 | fig.canvas.print_figure(bytes_io, format=fmt, bbox_inches='tight', |
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107 | 108 | facecolor=fc, edgecolor=ec, dpi=dpi) |
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108 | 109 | data = bytes_io.getvalue() |
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109 | 110 | return data |
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110 | 111 | |
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111 | def pngxy(data): | |
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112 | """read the width/height from a PNG header""" | |
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113 | ihdr = data.index(b'IHDR') | |
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114 | # next 8 bytes are width/height | |
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115 | w4h4 = data[ihdr+4:ihdr+12] | |
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116 | return struct.unpack('>ii', w4h4) | |
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117 | ||
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118 | 112 | def retina_figure(fig): |
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119 | 113 | """format a figure as a pixel-doubled (retina) PNG""" |
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120 | 114 | pngdata = print_figure(fig, fmt='retina') |
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121 | w, h = pngxy(pngdata) | |
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115 | w, h = _pngxy(pngdata) | |
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122 | 116 | metadata = dict(width=w//2, height=h//2) |
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123 | 117 | return pngdata, metadata |
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124 | 118 |
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