diff --git a/ofdgo_font_info.go b/ofdgo_font_info.go
index 2f40f4d..77e7027 100644
--- a/ofdgo_font_info.go
+++ b/ofdgo_font_info.go
@@ -168,10 +168,18 @@ func (r *Renderer) fontInfo(font Font) FontInfo {
 		Embedded:   font.FontFile != "",
 	}
 	if info.Embedded {
-		file, err := r.Reader.openFile(r.Reader.ResPath(font.FontFile))
-		if err == nil {
-			_, err = io.Copy(io.Discard, file)
-			file.Close()
+		name := r.Reader.ResPath(font.FontFile)
+		var err error
+		if !r.Reader.fontFilesChecked[name] {
+			var file io.ReadCloser
+			file, err = r.Reader.openFile(name)
+			if err == nil {
+				_, err = io.Copy(io.Discard, file)
+				file.Close()
+				if err == nil {
+					r.Reader.fontFilesChecked[name] = true
+				}
+			}
 		}
 		if err == nil {
 			info.Status = FontStatusEmbedded
diff --git a/ofdgo_reader.go b/ofdgo_reader.go
index 58d4c65..2d5c289 100644
--- a/ofdgo_reader.go
+++ b/ofdgo_reader.go
@@ -31,8 +31,10 @@ type Reader struct {
 	OFD                       *OFD
 	RootDir                   string
 	ResMap                    map[string]string
+	resourcesRead             map[string]bool
 	fontCache                 map[string]*Font
 	fontResourcesRead         bool
+	fontFilesChecked          map[string]bool
 	colorSpaceCache           map[string]*ColorSpace
 	drawParamCache            map[string]*DrawParam
 	compositeGraphicUnitCache map[string]*CompositeGraphicUnit
@@ -76,7 +78,9 @@ func (r *Reader) initRoot() error {
 	}
 	r.OFD = &ofd
 	r.ResMap = make(map[string]string)
+	r.resourcesRead = make(map[string]bool)
 	r.fontCache = make(map[string]*Font)
+	r.fontFilesChecked = make(map[string]bool)
 	r.colorSpaceCache = make(map[string]*ColorSpace)
 	r.drawParamCache = make(map[string]*DrawParam)
 	r.compositeGraphicUnitCache = make(map[string]*CompositeGraphicUnit)
@@ -182,6 +186,9 @@ func (r *Reader) loadRes(resPath string) {
 		return
 	}
 	fullPath := r.ResPath(resPath)
+	if r.resourcesRead[fullPath] {
+		return
+	}
 	data, err := r.readFile(fullPath)
 	if err != nil {
 		return
@@ -217,6 +224,7 @@ func (r *Reader) loadRes(resPath string) {
 		cgu := &res.CompositeGraphicUnits.CompositeGraphicUnit[i]
 		r.compositeGraphicUnitCache[cgu.ID] = cgu
 	}
+	r.resourcesRead[fullPath] = true
 }
 
 // resolveResourcePath 解析资源文件路径
diff --git a/ofdgo_renderer_output.go b/ofdgo_renderer_output.go
index ee27d47..41e62f3 100644
--- a/ofdgo_renderer_output.go
+++ b/ofdgo_renderer_output.go
@@ -26,16 +26,37 @@ import (
 	"github.com/tdewolff/canvas/renderers/rasterizer"
 )
 
+// rasterRenderer 保留页面物理尺寸的光栅渲染器
+type rasterRenderer struct {
+	*rasterizer.Rasterizer
+	width, height float64
+}
+
+// Size 返回页面物理尺寸
+// 返回: float64 宽度, float64 高度
+func (r *rasterRenderer) Size() (float64, float64) {
+	return r.width, r.height
+}
+
 // RenderToImage 渲染为光栅图
 // 入参: page 页面内容
 // 返回: image.Image 图像对象, error 错误信息
 func (r *Renderer) RenderToImage(page *PageContent) (image.Image, error) {
-	c, err := r.RenderPage(page)
+	box, err := r.GetPageBox(page)
 	if err != nil {
 		return nil, err
 	}
 	dpmm := r.DPI / 25.4
-	return rasterizer.Draw(c, canvas.DPMM(dpmm), canvas.DefaultColorSpace), nil
+	raster := &rasterRenderer{
+		Rasterizer: rasterizer.New(box.W, box.H, canvas.DPMM(dpmm), canvas.DefaultColorSpace),
+		width:      box.W,
+		height:     box.H,
+	}
+	if err := r.RenderPageToContext(canvas.NewContext(raster), page); err != nil {
+		return nil, err
+	}
+	raster.Close()
+	return raster.Image, nil
 }
 
 // RenderToSVG 渲染为SVG