use font metric to better display help page (to exted to other pages in future)

ft.c

@@ -171,7 +171,7 @@ static int getKerning(lua_State *L) {
 	return 1;
 }
 
-static int getHeight(lua_State *L) {
+static int getHeightAndAscender(lua_State *L) {
 	FT_Face *face = (FT_Face*) luaL_checkudata(L, 1, "ft_face");
 
 	double pixels_height,pixels_ascender;
@@ -206,7 +206,7 @@ static const struct luaL_Reg ft_face_meth[] = {
 	{"renderGlyph", renderGlyph},
 	{"hasKerning", hasKerning},
 	{"getKerning", getKerning},
-	{"getHeight", getHeight},
+	{"getHeightAndAscender", getHeightAndAscender},
 	{"done", doneFace},
 	{"__gc", doneFace},
 	{NULL, NULL}

helppage.lua

@@ -7,11 +7,6 @@ require "selectmenu"
 require "commands"
 
 HelpPage = {
-	-- Other Class vars:
-
-	-- spacing between lines
-	spacing = 25,
-
 	-- state buffer
 	commands = nil,
 	items = 0,
@@ -21,16 +16,13 @@ HelpPage = {
 -- Other Class vars:
 
 -- font for displaying keys
-HelpPage.fsize = 20
-HelpPage.face, HelpPage.fhash = Font:getFaceAndHash(HelpPage.fsize, "mono")
+HelpPage.mFace, HelpPage.mHash = Font:getFaceAndHash(20, "mono")
 -- font for displaying help messages
-HelpPage.hfsize = 20
-HelpPage.hface, HelpPage.hfhash = Font:getFaceAndHash(HelpPage.hfsize, "sans")
+HelpPage.sFace, HelpPage.sHash = Font:getFaceAndHash(20, "sans")
 -- font for paging display
-HelpPage.ffsize = 15
-HelpPage.fface, HelpPage.ffhash = Font:getFaceAndHash(HelpPage.ffsize, "sans")
+HelpPage.fFace, HelpPage.fHash = Font:getFaceAndHash(15, "sans")
 
-function HelpPage:show(ypos, height,commands)
+function HelpPage:show(ypos,height,commands)
 	self.commands = {}
 	self.items = 0
 	local keys = {}
@@ -44,28 +36,39 @@ function HelpPage:show(ypos, height,commands)
 		end
 	end
 	table.sort(self.commands,function(w1,w2) return w1.order<w2.order end)
-	local perpage = math.floor( (height - 1 * (self.ffsize + 5)) / self.spacing )
+
+	local mFaceHeight, mFaceAscender = self.mFace:getHeightAndAscender();
+	local fFaceHeight, fFaceAscender = self.fFace:getHeightAndAscender();
+	print(mFaceHeight.."-"..mFaceAscender)
+	print(fFaceHeight.."-"..fFaceAscender)
+	mFaceHeight = math.ceil(mFaceHeight)
+	mFaceAscender = math.ceil(mFaceAscender)
+	fFaceHeight = math.ceil(fFaceHeight)
+	fFaceAscender = math.ceil(fFaceAscender)
+	local spacing = mFaceHeight + 5
+
+	local perpage = math.floor( (height - ypos - 1 * (fFaceHeight + 5)) / spacing )
 	local pagedirty = true
 
 	while true do
 		if pagedirty then
-			fb.bb:paintRect(0, ypos, fb.bb:getWidth(), height, 0)
+			fb.bb:paintRect(0, 0, fb.bb:getWidth(), height, 0)
 			local c
 			local max_x = 0
 			for c = 1, perpage do
 				local i = (self.page - 1) * perpage + c
 				if i <= self.items then
-					local pen_x = renderUtf8Text(fb.bb, 5, ypos + self.spacing*c, self.face, self.fhash, self.commands[i].shortcut, true)
+					local pen_x = renderUtf8Text(fb.bb, 5, ypos + spacing*c, self.mFace, self.mHash, self.commands[i].shortcut, true)
 					max_x = math.max(max_x, pen_x)
 				end
 			end
 			for c = 1, perpage do
 				local i = (self.page - 1) * perpage + c
 				if i <= self.items then
-					renderUtf8Text(fb.bb, max_x + 20, ypos + self.spacing*c, self.hface, self.hfhash, self.commands[i].help, true)
+					renderUtf8Text(fb.bb, max_x + 20, ypos + spacing*c, self.sFace, self.sHash, self.commands[i].help, true)
 				end
 			end
-			renderUtf8Text(fb.bb, 5, height - math.floor(self.ffsize * 0.4), self.fface, self.ffhash,
+			renderUtf8Text(fb.bb, 5, height - fFaceHeight + fFaceAscender - 5, self.fFace, self.fHash,
 				"Page "..self.page.." of "..math.ceil(self.items / perpage).."  - click Back to close this page", true)
 			markerdirty = true
 		end

rendertext.lua

@@ -88,10 +88,10 @@ function renderUtf8Text(buffer, x, y, face, facehash, text, kerning)
 			if kerning and prevcharcode then
 				local kern = face:getKerning(prevcharcode, charcode)
 				pen_x = pen_x + kern
-				--print("prev:"..prevcharcode.." curr:"..charcode.." kern:"..kern)
+				--print("prev:"..string.char(prevcharcode).." curr:"..string.char(charcode).." pen_x:"..pen_x.." kern:"..kern)
 				buffer:addblitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			else
-				--print(" curr:"..charcode)
+				--print(" curr:"..string.char(charcode))
 				buffer:blitFrom(glyph.bb, x + pen_x + glyph.l, y - glyph.t, 0, 0, glyph.bb:getWidth(), glyph.bb:getHeight())
 			end
 			pen_x = pen_x + glyph.ax

rendertext_example.lua

@@ -18,7 +18,7 @@ end
 width, height = fb:getSize()
 fb.bb:paintRect(5,5,width-5,height-5,4);
 
-faceHeight, faceAscender = face:getHeight();
+faceHeight, faceAscender = face:getHeightAndAscender();
 print("face height:"..tostring(faceHeight).." - ascender:"..faceAscender)
 faceHeight = math.ceil(faceHeight)
 faceAscender = math.ceil(faceAscender)