diff --git a/core/fxge/agg/fx_agg_driver.cpp b/core/fxge/agg/fx_agg_driver.cpp
index b123566..3d68600 100644
--- a/core/fxge/agg/fx_agg_driver.cpp
+++ b/core/fxge/agg/fx_agg_driver.cpp
@@ -1361,7 +1361,7 @@
 
 bool CFX_AggDeviceDriver::StartDIBits(
     const RetainPtr<const CFX_DIBBase>& pSource,
-    int bitmap_alpha,
+    float alpha,
     uint32_t argb,
     const CFX_Matrix& matrix,
     const FXDIB_ResampleOptions& options,
@@ -1371,8 +1371,8 @@
     return true;
 
   *handle = std::make_unique<CFX_ImageRenderer>(
-      m_pBitmap, m_pClipRgn.get(), pSource, bitmap_alpha, argb, matrix, options,
-      m_bRgbByteOrder);
+      m_pBitmap, m_pClipRgn.get(), pSource, FXSYS_roundf(alpha * 255), argb,
+      matrix, options, m_bRgbByteOrder);
   return true;
 }
 
diff --git a/core/fxge/agg/fx_agg_driver.h b/core/fxge/agg/fx_agg_driver.h
index c39725d..db4a9a0 100644
--- a/core/fxge/agg/fx_agg_driver.h
+++ b/core/fxge/agg/fx_agg_driver.h
@@ -83,7 +83,7 @@
                      const FXDIB_ResampleOptions& options,
                      BlendMode blend_type) override;
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pSource,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t argb,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/cfx_renderdevice.cpp b/core/fxge/cfx_renderdevice.cpp
index 7816d92..48ed249 100644
--- a/core/fxge/cfx_renderdevice.cpp
+++ b/core/fxge/cfx_renderdevice.cpp
@@ -990,8 +990,8 @@
     const FXDIB_ResampleOptions& options,
     std::unique_ptr<CFX_ImageRenderer>* handle,
     BlendMode blend_mode) {
-  return m_pDeviceDriver->StartDIBits(pBitmap, bitmap_alpha, argb, matrix,
-                                      options, handle, blend_mode);
+  return m_pDeviceDriver->StartDIBits(pBitmap, bitmap_alpha / 255.0f, argb,
+                                      matrix, options, handle, blend_mode);
 }
 
 bool CFX_RenderDevice::ContinueDIBits(CFX_ImageRenderer* handle,
diff --git a/core/fxge/renderdevicedriver_iface.h b/core/fxge/renderdevicedriver_iface.h
index e1020ca..5120ebb 100644
--- a/core/fxge/renderdevicedriver_iface.h
+++ b/core/fxge/renderdevicedriver_iface.h
@@ -88,7 +88,7 @@
                              const FXDIB_ResampleOptions& options,
                              BlendMode blend_type) = 0;
   virtual bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                           int bitmap_alpha,
+                           float alpha,
                            uint32_t color,
                            const CFX_Matrix& matrix,
                            const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index e410259..9435bb4 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -576,17 +576,18 @@
 
 void SetBitmapPaint(bool is_mask,
                     bool anti_alias,
-                    int bitmap_alpha,
+                    float alpha,
                     uint32_t argb,
                     BlendMode blend_type,
                     SkPaint* paint) {
-  DCHECK_GE(bitmap_alpha, 0);
-  DCHECK_LE(bitmap_alpha, 255);
+  DCHECK_GE(alpha, 0.0f);
+  DCHECK_LE(alpha, 1.0f);
 
-  if (is_mask)
+  if (is_mask) {
     paint->setColor(argb);
-  else if (bitmap_alpha != 255)
-    paint->setAlpha(bitmap_alpha);
+  } else if (alpha != 1.0f) {
+    paint->setAlphaf(alpha);
+  }
 
   paint->setAntiAlias(anti_alias);
   paint->setBlendMode(GetSkiaBlendMode(blend_type));
@@ -1395,15 +1396,15 @@
     return true;
   }
 
-  CFX_Matrix m = CFX_RenderDevice::GetFlipMatrix(
+  CFX_Matrix matrix = CFX_RenderDevice::GetFlipMatrix(
       pBitmap->GetWidth(), pBitmap->GetHeight(), left, top);
 
   // `bNoSmoothing` prevents linear sampling when rendering bitmaps.
   FXDIB_ResampleOptions sampling_options;
   sampling_options.bNoSmoothing = true;
 
-  return StartDIBitsSkia(pBitmap, src_rect, 0xFF, color, m, sampling_options,
-                         blend_type);
+  return StartDIBitsSkia(pBitmap, src_rect, /*alpha=*/1.0f, color, matrix,
+                         sampling_options, blend_type);
 }
 
 bool CFX_SkiaDeviceDriver::StretchDIBits(
@@ -1419,8 +1420,8 @@
   if (m_pBitmap->GetBuffer().empty())
     return true;
 
-  CFX_Matrix m = CFX_RenderDevice::GetFlipMatrix(dest_width, dest_height,
-                                                 dest_left, dest_top);
+  CFX_Matrix matrix = CFX_RenderDevice::GetFlipMatrix(dest_width, dest_height,
+                                                      dest_left, dest_top);
   SkAutoCanvasRestore scoped_save_restore(m_pCanvas, /*doSave=*/true);
   SkRect skClipRect = SkRect::MakeLTRB(pClipRect->left, pClipRect->bottom,
                                        pClipRect->right, pClipRect->top);
@@ -1431,21 +1432,21 @@
   sampling_options.bNoSmoothing = true;
 
   return StartDIBitsSkia(
-      pSource, FX_RECT(0, 0, pSource->GetWidth(), pSource->GetHeight()), 0xFF,
-      color, m, sampling_options, blend_type);
+      pSource, FX_RECT(0, 0, pSource->GetWidth(), pSource->GetHeight()),
+      /*alpha=*/1.0f, color, matrix, sampling_options, blend_type);
 }
 
 bool CFX_SkiaDeviceDriver::StartDIBits(
     const RetainPtr<const CFX_DIBBase>& pSource,
-    int bitmap_alpha,
+    float alpha,
     uint32_t color,
     const CFX_Matrix& matrix,
     const FXDIB_ResampleOptions& options,
     std::unique_ptr<CFX_ImageRenderer>* handle,
     BlendMode blend_type) {
   return StartDIBitsSkia(
-      pSource, FX_RECT(0, 0, pSource->GetWidth(), pSource->GetHeight()),
-      bitmap_alpha, color, matrix, options, blend_type);
+      pSource, FX_RECT(0, 0, pSource->GetWidth(), pSource->GetHeight()), alpha,
+      color, matrix, options, blend_type);
 }
 
 bool CFX_SkiaDeviceDriver::ContinueDIBits(CFX_ImageRenderer* handle,
@@ -1573,7 +1574,7 @@
 bool CFX_SkiaDeviceDriver::StartDIBitsSkia(
     const RetainPtr<const CFX_DIBBase>& pSource,
     const FX_RECT& src_rect,
-    int bitmap_alpha,
+    float alpha,
     uint32_t color,
     const CFX_Matrix& matrix,
     const FXDIB_ResampleOptions& options,
@@ -1594,8 +1595,8 @@
     SetBitmapMatrix(matrix, width, height, &skMatrix);
     m_pCanvas->concat(skMatrix);
     SkPaint paint;
-    SetBitmapPaint(pSource->IsMaskFormat(), !m_FillOptions.aliased_path,
-                   bitmap_alpha, color, blend_type, &paint);
+    SetBitmapPaint(pSource->IsMaskFormat(), !m_FillOptions.aliased_path, alpha,
+                   color, blend_type, &paint);
 
     bool use_interpolate_bilinear = options.bInterpolateBilinear;
     if (!use_interpolate_bilinear) {
diff --git a/core/fxge/skia/fx_skia_device.h b/core/fxge/skia/fx_skia_device.h
index 6460c96..00626db 100644
--- a/core/fxge/skia/fx_skia_device.h
+++ b/core/fxge/skia/fx_skia_device.h
@@ -121,7 +121,7 @@
                      BlendMode blend_type) override;
 
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t color,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,
@@ -209,7 +209,7 @@
 
   bool StartDIBitsSkia(const RetainPtr<const CFX_DIBBase>& pSource,
                        const FX_RECT& src_rect,
-                       int bitmap_alpha,
+                       float alpha,
                        uint32_t color,
                        const CFX_Matrix& matrix,
                        const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/cgdi_display_driver.cpp b/core/fxge/win32/cgdi_display_driver.cpp
index a9f2434..df89fcc 100644
--- a/core/fxge/win32/cgdi_display_driver.cpp
+++ b/core/fxge/win32/cgdi_display_driver.cpp
@@ -209,7 +209,7 @@
 }
 
 bool CGdiDisplayDriver::StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                                    int bitmap_alpha,
+                                    float alpha,
                                     uint32_t color,
                                     const CFX_Matrix& matrix,
                                     const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/cgdi_display_driver.h b/core/fxge/win32/cgdi_display_driver.h
index a3e544d..4b71328 100644
--- a/core/fxge/win32/cgdi_display_driver.h
+++ b/core/fxge/win32/cgdi_display_driver.h
@@ -46,7 +46,7 @@
                      const FXDIB_ResampleOptions& options,
                      BlendMode blend_type) override;
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t color,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/cgdi_printer_driver.cpp b/core/fxge/win32/cgdi_printer_driver.cpp
index 3e6b41c..706aa5a 100644
--- a/core/fxge/win32/cgdi_printer_driver.cpp
+++ b/core/fxge/win32/cgdi_printer_driver.cpp
@@ -119,13 +119,13 @@
 }
 
 bool CGdiPrinterDriver::StartDIBits(const RetainPtr<const CFX_DIBBase>& pSource,
-                                    int bitmap_alpha,
+                                    float alpha,
                                     uint32_t color,
                                     const CFX_Matrix& matrix,
                                     const FXDIB_ResampleOptions& options,
                                     std::unique_ptr<CFX_ImageRenderer>* handle,
                                     BlendMode blend_type) {
-  if (bitmap_alpha < 255 || pSource->IsAlphaFormat() ||
+  if (alpha != 1.0f || pSource->IsAlphaFormat() ||
       (pSource->IsMaskFormat() && (pSource->GetBPP() != 1))) {
     return false;
   }
diff --git a/core/fxge/win32/cgdi_printer_driver.h b/core/fxge/win32/cgdi_printer_driver.h
index 2477399..bf8f82c 100644
--- a/core/fxge/win32/cgdi_printer_driver.h
+++ b/core/fxge/win32/cgdi_printer_driver.h
@@ -37,7 +37,7 @@
                      const FXDIB_ResampleOptions& options,
                      BlendMode blend_type) override;
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t color,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/cps_printer_driver.cpp b/core/fxge/win32/cps_printer_driver.cpp
index f24f4ab..71678dc 100644
--- a/core/fxge/win32/cps_printer_driver.cpp
+++ b/core/fxge/win32/cps_printer_driver.cpp
@@ -185,17 +185,15 @@
 }
 
 bool CPSPrinterDriver::StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                                   int bitmap_alpha,
+                                   float alpha,
                                    uint32_t color,
                                    const CFX_Matrix& matrix,
                                    const FXDIB_ResampleOptions& options,
                                    std::unique_ptr<CFX_ImageRenderer>* handle,
                                    BlendMode blend_type) {
-  if (blend_type != BlendMode::kNormal)
+  if (blend_type != BlendMode::kNormal || alpha != 1.0f) {
     return false;
-
-  if (bitmap_alpha < 255)
-    return false;
+  }
 
   *handle = nullptr;
   return m_PSRenderer.DrawDIBits(pBitmap, color, matrix, options);
diff --git a/core/fxge/win32/cps_printer_driver.h b/core/fxge/win32/cps_printer_driver.h
index e4b3197..baf9a04 100644
--- a/core/fxge/win32/cps_printer_driver.h
+++ b/core/fxge/win32/cps_printer_driver.h
@@ -61,7 +61,7 @@
                      const FXDIB_ResampleOptions& options,
                      BlendMode blend_type) override;
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t color,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/ctext_only_printer_driver.cpp b/core/fxge/win32/ctext_only_printer_driver.cpp
index 470fa5c..6a69240 100644
--- a/core/fxge/win32/ctext_only_printer_driver.cpp
+++ b/core/fxge/win32/ctext_only_printer_driver.cpp
@@ -116,7 +116,7 @@
 
 bool CTextOnlyPrinterDriver::StartDIBits(
     const RetainPtr<const CFX_DIBBase>& pBitmap,
-    int bitmap_alpha,
+    float alpha,
     uint32_t color,
     const CFX_Matrix& matrix,
     const FXDIB_ResampleOptions& options,
diff --git a/core/fxge/win32/ctext_only_printer_driver.h b/core/fxge/win32/ctext_only_printer_driver.h
index d47b838..3054fdb 100644
--- a/core/fxge/win32/ctext_only_printer_driver.h
+++ b/core/fxge/win32/ctext_only_printer_driver.h
@@ -52,7 +52,7 @@
                      const FXDIB_ResampleOptions& options,
                      BlendMode blend_type) override;
   bool StartDIBits(const RetainPtr<const CFX_DIBBase>& pBitmap,
-                   int bitmap_alpha,
+                   float alpha,
                    uint32_t color,
                    const CFX_Matrix& matrix,
                    const FXDIB_ResampleOptions& options,