Don't show SW dither toggle on devices w/ HW dithering

frontend/dispatcher.lua

@@ -190,7 +190,7 @@ local settingsList = {
     kopt_contrast = {category="absolutenumber", paging=true},
     kopt_page_opt = {category="configurable", paging=true},
     kopt_hw_dithering = {category="configurable", paging=true, condition=Device:hasEinkScreen() and Device:canHWDither()},
-    kopt_sw_dithering = {category="configurable", paging=true, condition=Device:hasEinkScreen() and Device.screen.fb_bpp == 8},
+    kopt_sw_dithering = {category="configurable", paging=true, condition=Device:hasEinkScreen() and not Device:canHWDither() and Device.screen.fb_bpp == 8},
     kopt_quality = {category="configurable", paging=true},
     kopt_doc_language = {category="string", paging=true},
     kopt_forced_ocr = {category="configurable", paging=true},

frontend/document/document.lua

@@ -497,7 +497,8 @@ function Document:drawPage(target, x, y, rect, pageno, zoom, rotation, gamma, re
     local tile = self:renderPage(pageno, rect, zoom, rotation, gamma, render_mode)
     -- Enable SW dithering if requested (only available in koptoptions)
     -- Much Like ReaderView, also enforce SW dithering in PicDocument if the device can't do HW dithering...
-    if (self.is_pic and CanvasContext:hasEinkScreen() and not CanvasContext:canHWDither() and CanvasContext.fb_bpp == 8) or (self.configurable.sw_dithering and self.configurable.sw_dithering == 1) then
+    if (self.is_pic and CanvasContext:hasEinkScreen() and not CanvasContext:canHWDither() and CanvasContext.fb_bpp == 8)
+    or (self.configurable.sw_dithering and self.configurable.sw_dithering == 1) then
         target:ditherblitFrom(tile.bb,
             x, y,
             rect.x - tile.excerpt.x,

frontend/ui/data/koptoptions.lua

@@ -497,7 +497,7 @@ This can also be used to remove some gray background or to convert a grayscale o
             },
             {
                 name = "hw_dithering",
-                name_text = _("HW Dithering"),
+                name_text = _("Dithering"),
                 toggle = {_("off"), _("on")},
                 values = {0, 1},
                 default_value = 0,
@@ -508,12 +508,12 @@ This can also be used to remove some gray background or to convert a grayscale o
             },
             {
                 name = "sw_dithering",
-                name_text = _("SW Dithering"),
+                name_text = _("Dithering"),
                 toggle = {_("off"), _("on")},
                 values = {0, 1},
                 default_value = 0,
                 advanced = true,
-                show = Device:hasEinkScreen() and Device.screen.fb_bpp == 8,
+                show = Device:hasEinkScreen() and not Device:canHWDither() and Device.screen.fb_bpp == 8,
                 name_text_hold_callback = optionsutil.showValues,
                 help_text = _([[Enable software dithering.]]),
             },