From 64af343d0e419266fd5cf5844466326074dab379 Mon Sep 17 00:00:00 2001
From: liuping <ping.1.liu@aptiv.com>
Date: Tue, 21 May 2024 08:50:38 +0800
Subject: [PATCH] fix blurry font issue when the DPI scale > 1.0   #163

---
 pkg/ant.imgui/main.lua                        |  1 +
 tools/editor/pkg/tools.editor/init_system.lua | 31 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/pkg/ant.imgui/main.lua b/pkg/ant.imgui/main.lua
index 8f440fbe7b..86dd711873 100644
--- a/pkg/ant.imgui/main.lua
+++ b/pkg/ant.imgui/main.lua
@@ -30,6 +30,7 @@ function ImGuiAnt.FontAtlasBuild(list)
         FontDatas[#FontDatas+1] = FontData
         local data, size = fastio.wrap(FontData)()
         ImFontConfig.MergeMode = i > 1
+        ImFontConfig.RasterizerDensity = config.RasterizerDensity
         atlas.AddFontFromMemoryTTF(data, size, config.SizePixels, ImFontConfig, glyphRanges(config.GlyphRanges))
     end
     atlas.Build()
diff --git a/tools/editor/pkg/tools.editor/init_system.lua b/tools/editor/pkg/tools.editor/init_system.lua
index 3adae44d44..2276666d47 100644
--- a/tools/editor/pkg/tools.editor/init_system.lua
+++ b/tools/editor/pkg/tools.editor/init_system.lua
@@ -21,6 +21,11 @@ local widget_utils      = require "widget.utils"
 
 local m = ecs.system 'init_system'
 
+local ImGui         = require "imgui"
+local ImGuiBackend  = require "imgui.backend"
+
+local dpi = {min=0.0, max=2.77, value=1, enabled=true}
+
 local function start_fileserver(luaexe, path)
 	local fsa = require "fileserver_adapter"
 	fsa.init(luaexe, path)
@@ -32,11 +37,13 @@ local function init_font()
 	fonts[#fonts+1] = {
 		FontPath = "/pkg/ant.resources.binary/font/Alibaba-PuHuiTi-Regular.ttf",
 		SizePixels = 18,
+		RasterizerDensity = dpi.value,
 		GlyphRanges = { 0x0020, 0xFFFF }
 	}
 	fonts[#fonts+1] = {
 		FontPath = "/pkg/tools.editor/resource/fonts/fa-solid-900.ttf",
 		SizePixels = 16,
+		RasterizerDensity = dpi.value,
 		GlyphRanges = {
 			0xf062, 0xf062, -- ICON_FA_ARROW_UP 			"\xef\x81\xa2"	U+f062
 			0xf063, 0xf063,	-- ICON_FA_ARROW_DOWN 			"\xef\x81\xa3"	U+f063
@@ -155,6 +162,30 @@ function m:data_changed()
 
 end
 
+function m:start_frame()
+    -- GetWindowDpiScale/GetMainViewport only availbled in start_frame/end_frame
+    if dpi.enabled then
+        local scale = ImGui.GetWindowDpiScale()
+        if scale == dpi.value then
+            dpi.enabled = false
+        end
+        -- calculate DPI scale
+        dpi.value = math.max(dpi.min, math.min(dpi.max, scale))
+    end
+end
+
+function m:final()
+    -- ImGui says: Can not modify a locked ImFontAtlas between NewFrame() and EndFrame/Render()
+    if dpi.enabled then
+        -- rebuild font atlas
+        init_font()
+        ImGuiBackend.RenderCreateFontsTexture()
+        dpi.enabled = false
+
+        log.warn(string.format('rebuild the font atlas due to the DPI scale changed dpi:1.0->%.2f', dpi.value))
+    end
+end
+
 function m:exit()
 	if global_data.fileserver and global_data.fileserver.subprocess then
 		global_data.fileserver.subprocess:wait()