From f49267e85b427a66523cff3efc236ec8db5e4051 Mon Sep 17 00:00:00 2001
From: Matthias Melcher <fltk@matthiasm.com>
Date: Sun, 1 Apr 2018 16:06:12 +0000
Subject: Android: Drawing RGB image data on the fly via callback

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12818 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/drivers/Android/Fl_Android_Graphics_Driver.H   |  7 ++-
 src/drivers/Android/Fl_Android_Graphics_Driver.cxx | 71 +++++++++++++++++++---
 2 files changed, 68 insertions(+), 10 deletions(-)

(limited to 'src')

diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver.H b/src/drivers/Android/Fl_Android_Graphics_Driver.H
index 198d32937..db57b97f6 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver.H
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver.H
@@ -75,11 +75,11 @@ protected:
   virtual void draw_image(const uchar* buf, int X,int Y,int W,int H, int D=3, int L=0) {}
   /** see fl_draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D, int L) */
   virtual void draw_image_mono(const uchar* buf, int X,int Y,int W,int H, int D=1, int L=0) {}
+#endif
   /** see fl_draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D) */
-  virtual void draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=3) {}
+  virtual void draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=3) override;
   /** see fl_draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D) */
-  virtual void draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1) {}
-#endif
+  virtual void draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D=1) override;
   /** \brief Draws an Fl_RGB_Image object using this graphics driver. */
   virtual void draw(Fl_RGB_Image * rgb,int XP, int YP, int WP, int HP, int cx, int cy) override;
   /** \brief Draws an Fl_Pixmap object using this graphics driver.
@@ -301,6 +301,7 @@ public:
   void make_current(Fl_Window*);
 
 protected:
+  static uint16_t make565(uchar r, uchar g, uchar b);
   static uint16_t make565(Fl_Color crgba);
   void rectf_unclipped(int x, int y, int w, int h);
   void xyline_unclipped(int x, int y, int x1);
diff --git a/src/drivers/Android/Fl_Android_Graphics_Driver.cxx b/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
index a53cb7795..943163521 100644
--- a/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
+++ b/src/drivers/Android/Fl_Android_Graphics_Driver.cxx
@@ -83,11 +83,11 @@ void Fl_Android_Graphics_Driver::make_current(Fl_Window *win)
 }
 
 
-static uint16_t  make565(int red, int green, int blue)
+uint16_t Fl_Android_Graphics_Driver::make565(uchar red,  uchar green, uchar blue)
 {
-    return (uint16_t)( ((red   << 8) & 0xf800) |
-                       ((green << 3) & 0x07e0) |
-                       ((blue  >> 3) & 0x001f) );
+    return (uint16_t)( ((((uint16_t)(red))   << 8) & 0xf800) |
+                       ((((uint16_t)(green)) << 3) & 0x07e0) |
+                       ((((uint16_t)(blue))  >> 3) & 0x001f) );
 }
 
 extern unsigned fl_cmap[256];
@@ -96,9 +96,9 @@ extern unsigned fl_cmap[256];
 uint16_t Fl_Android_Graphics_Driver::make565(Fl_Color crgba)
 {
   if (crgba<0x00000100) crgba = fl_cmap[crgba];
-    return (uint16_t)( ((crgba >>16) & 0xf800) |
-                       ((crgba >>13) & 0x07e0) |
-                       ((crgba >>11) & 0x001f) );
+    return (uint16_t)( ((crgba >> 16) & 0xf800) |
+                       ((crgba >> 13) & 0x07e0) |
+                       ((crgba >> 11) & 0x001f) );
 }
 
 
@@ -1116,6 +1116,63 @@ void Fl_Android_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP,
   }
 }
 
+/*
+ * Draw some graphics line-by-line directly onto this surface
+ * TODO: I did not find documentation on the possible values of D. If D is four, does that
+ * mean that the fourth value must be an alpha value, and should that be applied here?
+ */
+void Fl_Android_Graphics_Driver::draw_image(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D)
+{
+  int srcDelta = abs(D);
+  for (const auto &it: pClippingRegion.overlapping(Fl_Rect_Region(X, Y, W, H))) {
+    Fl_Rect_Region *r = &it->clipped_rect();
+    uchar *buf = (uchar*)malloc(srcDelta*r->w());
+    int rBottom = r->bottom();
+    int rRight = r->right();
+    for (int iy=r->top(); iy<rBottom;iy++) {
+      cb(data, r->left()-X, iy-Y, r->w(), buf);
+      uchar *src = buf;
+      uint16_t *dst = pBits + iy*pStride + r->left();
+      for (int ix=r->left();ix<rRight;ix++) {
+        uint16_t c = make565(src[0], src[1], src[2]);
+        src += srcDelta;
+        *dst++ = c;
+      }
+    }
+    free(buf);
+  }
+}
+
+/*
+ * Draw some graphics line-by-line directly onto this surface
+ * TODO: I did not find documentation on the possible values of D. If D is two, does that
+ * mean that the fourth value must be an alpha value, and should that be applied here?
+ * If it is three, doe we need to convert RGB to grayscale?
+ * What exactly does a negative value mean? Where is this all documented? Sigh.
+ */
+void Fl_Android_Graphics_Driver::draw_image_mono(Fl_Draw_Image_Cb cb, void* data, int X,int Y,int W,int H, int D)
+{
+  int srcDelta = abs(D);
+  for (const auto &it: pClippingRegion.overlapping(Fl_Rect_Region(X, Y, W, H))) {
+    Fl_Rect_Region *r = &it->clipped_rect();
+    uchar *buf = (uchar*)malloc(srcDelta*r->w());
+    int rBottom = r->bottom();
+    int rRight = r->right();
+    for (int iy=r->top(); iy<rBottom;iy++) {
+      cb(data, r->left()-X, iy-Y, r->w(), buf);
+      uchar *src = buf;
+      uint16_t *dst = pBits + iy*pStride + r->left();
+      for (int ix=r->left();ix<rRight;ix++) {
+        uchar l = src[0];
+        uint16_t c = make565(l, l, l);
+        src += srcDelta;
+        *dst++ = c;
+      }
+    }
+    free(buf);
+  }
+}
+
 
 void Fl_Android_Graphics_Driver::uncache(Fl_RGB_Image*, fl_uintptr_t &id_, fl_uintptr_t&)
 {
-- 
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