FIX: Circular imports in toolbar_plot and transform_color_mapper

[achabotl]

Import directly from the module where each class is implemented instead of importing from chaco.api.

[jvkersch]

Looks good; why not go the whole hog and prefer direct module imports over imports from chaco.api everywhere?

$ rg -g '!tests' "chaco.api"
function_image_data.py
3:from chaco.api import DataRange2D, ImageData

overlays/container_overlay.py
10:from chaco.api import PlotComponent

overlays/coordinate_line_overlay.py
11:from chaco.api import AbstractOverlay

overlays/databox.py
7:from chaco.api import AbstractOverlay

tools/dataprinter.py
11:from chaco.api import BaseXYPlot

tools/highlight_tool.py
11:from chaco.api import BasePlotContainer

tools/image_inspector_tool.py
9:from chaco.api import AbstractOverlay, ImagePlot, TextBoxOverlay

tools/line_inspector.py
10:from chaco.api import BaseXYPlot, Base2DPlot

tools/range_selection_overlay.py
12:from chaco.api import AbstractOverlay, arg_find_runs, GridMapper, AbstractMapper

tools/draw_points_tool.py
11:from chaco.api import ArrayDataSource

tools/traits_tool.py
9:from chaco.api import PlotAxis, ColorBar

tools/line_segment_tool.py
13:from chaco.api import AbstractOverlay

tools/range_selection.py
12:from chaco.api import AbstractController

tools/save_tool.py
59:        from chaco.api import PlotGraphicsContext

tools/regression_lasso.py
14:from chaco.api import LassoOverlay, Label

tools/lasso_selection.py
13:from chaco.api import AbstractController, AbstractDataSource, \

shell/plot_maker.py
16:from chaco.api import (create_line_plot, create_scatter_plot,

layers/status_layer.py
7:from chaco.api import AbstractOverlay

layers/svg_range_selection_overlay.py
7:from chaco.api import GridMapper

shell/scaly_plot.py
6:from chaco.api import (DataRange2D, LinearMapper, LogMapper,

shell/commands.py
14:from chaco.api import Plot, color_map_name_dict
800:        from chaco.api import PlotGraphicsContext

tests_with_backend/test_highlight_tool.py
8:from chaco.api import Plot, ArrayPlotData

tests_with_backend/test_2d_case.py
3:from chaco.api import Plot, ArrayPlotData

ui/popupable_plot.py
3:from chaco.api import VPlotContainer

[achabotl]

The hog is now whole. No more chaco.api imports anywhere. No more chaco.tools.api and chaco.scales.api either.

Ready for review.

[jvkersch]

That's great, thanks for doing this! There are some import errors from chaco.scales, but presumably those can be fixed easily.

[achabotl]

Yes, that was an easy fix. I got bitten by the fact that python etstools.py test tests an installed version of Chaco (into the test env), and not an editable version.

[jvkersch]

LGTM. Thanks @achabotl !