fix: calculate output image size not depending on scale/crs

[Kanahiro]

Issue

close #74 close #50 close #51

変更内容:Description

• before: calculate image size by extent, dpi and scale
• after: calculate image size by extent and dpi

テスト手順:Test

• Check that wms layer is exported in a reasonable resolution for mapCanvas DPI.

その他:Notes

• 特になし

[bordoray]

Low/Middle Scale maps looks giving too high resolution

1:384000 Process time longer than usual: 20 minutes

WMTS

Result (542 MB)

1:96000 Process time longer than usual: 30sec~1 minutes

WMTS

Result (32MB)

1:24000 LGTM

High scale looks blurry

1:6000 WMTS

Result

1:1500 WMTS

Result

1:368 WMTS

Result

[Kanahiro]

@bordoray Thank you for testing. I've changed approach:

• accept any crs
• calculate output image size as it is same to mapcanvas
  • this means output image is rendered as same to mapcanvas too.

This resolves Issue #50, #51 as well.