[Bug] Maps with legend do not save properly as png or tiff files

[baharmon]

Describe the bug
On GRASS 7.8.3 on Windows 10 maps with a legend do not save properly as png or tiff files with the Save display to file dialog in the GUI or with a Cairo monitor using a Python script. Maps are saved as pngs with transparent cells except for the legend. Without a legend maps save properly. This is the case for both raster and vector legends. Maps, however, do save properly with m.printws.

To Reproduce

1. Start GRASS 7.8.3 in the ncspm_basic_grass7 location
2. add elevation@PERMANENT to the map display
3. Add a legend for elevation raster with d.legend
4. Save a png of the elevation raster with a legend using Save display to file
5. Open the saved png

Expected behavior
Should save a png file with the map and legend.

Screenshots

Elevation map with legend from GRASS 7.7	Elevation map with legend from GRASS 7.8.3

System description (please complete the following information):

• Operating System: Windows 10
• GRASS GIS version: 7.8.3

[tmszi]

It works properly with a newer version of wxPython, tested with 4.1.0 msw (phoenix) wxWidgets 3.1.4.

Simple test script: overlay.py (save imgs below in the same directory as your script overlay.py). After run check result.png image file.

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os

from PIL import Image

import wx
import wx.adv


dirname = os.path.dirname(__file__)

BG_MAP = os.path.join(dirname, 'map.png')
MAP_LEGEND = os.path.join(dirname, 'map_legend.png')
RESULT = os.path.join(dirname, 'result.png')


def PilImageToWxImage(pilImage, copyAlpha=True):
    """Convert PIL image to wx.Image

    Based on http://wiki.wxpython.org/WorkingWithImages
    """

    hasAlpha = pilImage.mode[-1] == 'A'
    if copyAlpha and hasAlpha:  # Make sure there is an alpha layer copy.
        wxImage = wx.Image(*pilImage.size)
        pilImageCopyRGBA = pilImage.copy()
        pilImageCopyRGB = pilImageCopyRGBA.convert('RGB')    # RGBA --> RGB
        fn = getattr(
            pilImageCopyRGB,
            "tobytes",
            getattr(
                pilImageCopyRGB,
                "tostring",
            ),
        )

        pilImageRgbData = fn()
        wxImage.SetData(pilImageRgbData)
        fn = getattr(
            pilImageCopyRGBA,
            "tobytes",
            getattr(
                pilImageCopyRGBA,
                "tostring",
            ),
        )
        # Create layer and insert alpha values.
        wxImage.SetAlpha(fn()[3::4])

    else:    # The resulting image will not have alpha.
        wxImage = wx.Image(*pilImage.size)
        pilImageCopy = pilImage.copy()
        # Discard any alpha from the PIL image.
        pilImageCopyRGB = pilImageCopy.convert('RGB')
        fn = getattr(
            pilImageCopyRGB,
            "tobytes",
            getattr(
                pilImageCopyRGB,
                "tostring",
            ),
        )
        pilImageRgbData = fn()
        wxImage.SetData(pilImageRgbData)

    return wxImage


def draw(pdc, coords, drawid, img):
    if drawid != 99:
        bg = wx.TRANSPARENT_BRUSH
    else:
        bg = wx.Brush(wx.WHITE)

    pdc.SetBackground(bg)

    bitmap = wx.Bitmap(img)
    w, h = bitmap.GetSize()
    pdc.DrawBitmap(
        bitmap, coords[0],
        coords[1],
        False,
    )  # draw the composite map
    pdc.SetIdBounds(drawid, wx.Rect(coords[0], coords[1], w, h))


def main():

    app = wx.App()

    pdc = wx.adv.PseudoDC()
    bg_map = wx.Image(BG_MAP, wx.BITMAP_TYPE_ANY)
    ibuffer = wx.Bitmap(
        max(1, bg_map.GetWidth()),
        max(1, bg_map.GetHeight()),
    )
    draw(pdc, (0, 0), 99, img=bg_map)

    legend_img = Image.open(MAP_LEGEND)
    imageBox = legend_img.getbbox()
    cropped = legend_img.crop(imageBox)
    legend = PilImageToWxImage(cropped)
    draw(pdc, (58, 324), 100, img=legend)

    dc = wx.BufferedDC(None, ibuffer)
    dc.Clear()
    pdc.DrawToDC(dc)

    ibuffer.SaveFile(RESULT, wx.BITMAP_TYPE_PNG)

    app.MainLoop()


if __name__ == '__main__':
    main()

Map (save as map.png file):

Map legend (save as map_legend.png file):

[neteler]

What is the state of this report?

[petrasovaa]

Thanks @tmszi for the analysis, it looks like the problem is resolved with newer wx version. Feel free to reopen if that is not the case.