diff --git a/frontend/document/djvudocument.lua b/frontend/document/djvudocument.lua
index fa91e1013..5d7808f8a 100644
--- a/frontend/document/djvudocument.lua
+++ b/frontend/document/djvudocument.lua
@@ -65,6 +65,14 @@ function DjvuDocument:invertTextYAxel(pageno, text_table)
 	return text_table
 end
 
+function DjvuDocument:getPageBBox(pageno)
+	if self.configurable.text_wrap ~= 1 and self.configurable.trim_page == 1 then
+		return self.koptinterface:getAutoBBox(self, pageno)
+	else
+		return Document.getPageBBox(self, pageno)
+	end
+end
+
 function DjvuDocument:getPageDimensions(pageno, zoom, rotation)
 	if self.configurable.text_wrap == 1 then
 		return self.koptinterface:getPageDimensions(self, pageno, zoom, rotation)
diff --git a/frontend/document/koptinterface.lua b/frontend/document/koptinterface.lua
index 8a9e84476..eeb87a75d 100644
--- a/frontend/document/koptinterface.lua
+++ b/frontend/document/koptinterface.lua
@@ -88,6 +88,27 @@ function KoptInterface:logReflowDuration(pageno, dur)
 	end
 end
 
+function KoptInterface:getAutoBBox(doc, pageno)
+	local bbox = {
+		x0 = 0, y0 = 0,
+		x1 = 0, y1 = 0,
+	}
+	local context_hash = self:getContextHash(doc, pageno, bbox)
+	local hash = "autobbox|"..context_hash
+	local cached = Cache:check(hash)
+	if not cached then
+		local page = doc._document:openPage(pageno)
+		local kc = self:getKOPTContext(doc, pageno, bbox)
+		bbox.x0, bbox.y0, bbox.x1, bbox.y1 = page:getAutoBBox(kc)
+		DEBUG("Auto detected bbox", bbox)
+		page:close()
+		Cache:insert(hash, CacheItem:new{ bbox = bbox })
+		return bbox
+	else
+		return cached.bbox
+	end
+end
+
 function KoptInterface:getReflowedDim(kc)
 	self:waitForContext(kc)
 	return kc:getPageDim()
diff --git a/frontend/document/pdfdocument.lua b/frontend/document/pdfdocument.lua
index 70075e200..c5fe50c7d 100644
--- a/frontend/document/pdfdocument.lua
+++ b/frontend/document/pdfdocument.lua
@@ -67,6 +67,14 @@ function PdfDocument:getUsedBBox(pageno)
 	return used
 end
 
+function PdfDocument:getPageBBox(pageno)
+	if self.configurable.text_wrap ~= 1 and self.configurable.trim_page == 1 then
+		return self.koptinterface:getAutoBBox(self, pageno)
+	else
+		return Document.getPageBBox(self, pageno)
+	end
+end
+
 function PdfDocument:getPageDimensions(pageno, zoom, rotation)
 	if self.configurable.text_wrap == 1 then
 		return self.koptinterface:getPageDimensions(self, pageno, zoom, rotation)
diff --git a/frontend/ui/data/koptoptions.lua b/frontend/ui/data/koptoptions.lua
index 8e52d64f4..0f611b895 100644
--- a/frontend/ui/data/koptoptions.lua
+++ b/frontend/ui/data/koptoptions.lua
@@ -57,8 +57,9 @@ KoptOptions = {
 				name = "page_margin",
 				name_text = PAGE_MARGIN_STR,
 				toggle = {SMALL_STR, MEDIUM_STR, LARGE_STR},
-				values = {0.06, 0.10, 0.14},
+				values = {0.05, 0.10, 0.15},
 				default_value = 0.10,
+				event = "MarginUpdate",
 			},
 			{
 				name = "line_spacing",
@@ -175,8 +176,9 @@ KoptOptions = {
 				name = "defect_size",
 				name_text = DEFECT_SIZE_STR,
 				toggle = {SMALL_STR, MEDIUM_STR, LARGE_STR},
-				values = {0.5, 1.0, 2.0},
+				values = {1.0, 8.0, 15.0},
 				default_value = 1.0,
+				event = "DefectSizeUpdate",
 			},
 			{
 				name = "quality",
diff --git a/frontend/ui/reader/readerview.lua b/frontend/ui/reader/readerview.lua
index 31ee8beae..e991aa74b 100644
--- a/frontend/ui/reader/readerview.lua
+++ b/frontend/ui/reader/readerview.lua
@@ -360,6 +360,21 @@ function ReaderView:onGammaUpdate(gamma)
 	end
 end
 
+function ReaderView:onDefectSizeUpdate()
+	self.ui:handleEvent(Event:new("ReZoom"))
+	self.ui:handleEvent(Event:new("InitScrollPageStates"))
+end
+
+function ReaderView:onPageCrop()
+	self.ui:handleEvent(Event:new("ReZoom"))
+	self.ui:handleEvent(Event:new("InitScrollPageStates"))
+end
+
+function ReaderView:onMarginUpdate()
+	self.ui:handleEvent(Event:new("ReZoom"))
+	self.ui:handleEvent(Event:new("InitScrollPageStates"))
+end
+
 function ReaderView:onSetViewMode(new_mode)
 	self.ui.view_mode = new_mode
 	self.ui.document:setViewMode(new_mode)
diff --git a/frontend/ui/reader/readerzooming.lua b/frontend/ui/reader/readerzooming.lua
index 105e2eced..2ab0b98ff 100644
--- a/frontend/ui/reader/readerzooming.lua
+++ b/frontend/ui/reader/readerzooming.lua
@@ -155,6 +155,11 @@ function ReaderZooming:onPageUpdate(new_page_no)
 	self:setZoom()
 end
 
+function ReaderZooming:onReZoom()
+	self:setZoom()
+	return true
+end
+
 function ReaderZooming:onHintPage()
 	if not self.view.hinting then return true end
 	if self.current_page < self.ui.document.info.number_of_pages then