From d4577f0d0acfcf0ce3e137de4600a0e59c52c6e9 Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Wed, 9 Mar 2016 11:40:13 +0000
Subject: Simplify Fl_OpenGL_Display_Device::capture_gl_rectangle() under Mac
 OS.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3-porting@11328 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx | 29 +++++--------------------
 1 file changed, 6 insertions(+), 23 deletions(-)

(limited to 'src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx')

diff --git a/src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx b/src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx
index a9a181f7c..505efd17d 100644
--- a/src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx
+++ b/src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx
@@ -41,11 +41,12 @@ Fl_OpenGL_Display_Device::Fl_OpenGL_Display_Device(Fl_OpenGL_Graphics_Driver *gr
 
 #ifdef FL_CFG_GFX_QUARTZ
 
+// convert BGRA to RGB and also exchange top and bottom
 uchar *convert_BGRA_to_RGB(uchar *baseAddress, int w, int h, int mByteWidth)
 {
   uchar *newimg = new uchar[3*w*h];
   uchar *to = newimg;
-  for (int i = 0; i < h; i++) {
+  for (int i = h-1; i >= 0; i--) {
     uchar *from = baseAddress + i * mByteWidth;
     for (int j = 0; j < w; j++, from += 4) {
 #if __ppc__
@@ -64,7 +65,6 @@ uchar *convert_BGRA_to_RGB(uchar *baseAddress, int w, int h, int mByteWidth)
 
 Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window* glw, int x, int y, int w, int h)
 {
-  const int bytesperpixel = 4;
   int factor = glw->pixels_per_unit();
   if (factor > 1) {
     w *= factor; h *= factor; x *= factor; y *= factor;
@@ -78,31 +78,16 @@ Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window* glw,
   glPixelStorei(GL_PACK_SKIP_ROWS, 0);
   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
   // Read a block of pixels from the frame buffer
-  int mByteWidth = w * bytesperpixel;
+  int mByteWidth = w * 4;
   mByteWidth = (mByteWidth + 3) & ~3;    // Align to 4 bytes
   uchar *baseAddress = new uchar[mByteWidth * h];
   glReadPixels(x, glw->pixel_h() - (y+h), w, h,
-               GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV,
-               baseAddress);
+               GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, baseAddress);
   glPopClientAttrib();
   baseAddress = convert_BGRA_to_RGB(baseAddress, w, h, mByteWidth);
-  mByteWidth = 3 * w;
-  
-  // GL gives a bottom-to-top image, convert it to top-to-bottom
-  uchar *tmp = new uchar[mByteWidth];
-  uchar *p = baseAddress ;
-  uchar *q = baseAddress + (h-1)*mByteWidth;
-  for (int i = 0; i < h/2; i++, p += mByteWidth, q -= mByteWidth) {
-    memcpy(tmp, p, mByteWidth);
-    memcpy(p, q, mByteWidth);
-    memcpy(q, tmp, mByteWidth);
-  }
-  delete[] tmp;
-  
-  Fl_RGB_Image *img = new Fl_RGB_Image(baseAddress, w, h, 3, mByteWidth);
+  Fl_RGB_Image *img = new Fl_RGB_Image(baseAddress, w, h, 3, 3 * w);
   img->alloc_array = 1;
   return img;
- 
 }
 #elif defined(FL_CFG_GFX_GDI) || defined(FL_CFG_GFX_XLIB)
 
@@ -110,7 +95,6 @@ Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window *glw,
 /* captures a rectangle of a Fl_Gl_Window window, and returns it as a RGB image
  */
 {
-  const int bytesperpixel = 3;
   glw->flush(); // forces a GL redraw, necessary for the glpuzzle demo
   // Read OpenGL context pixels directly.
   // For extra safety, save & restore OpenGL states that are changed
@@ -120,14 +104,13 @@ Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window *glw,
   glPixelStorei(GL_PACK_SKIP_ROWS, 0);
   glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
   // Read a block of pixels from the frame buffer
-  int mByteWidth = w * bytesperpixel;
+  int mByteWidth = w * 3;
   mByteWidth = (mByteWidth + 3) & ~3;    // Align to 4 bytes
   uchar *baseAddress = new uchar[mByteWidth * h];
   glReadPixels(x, glw->pixel_h() - (y+h), w, h,
                GL_RGB, GL_UNSIGNED_BYTE,
                baseAddress);
   glPopClientAttrib();
-  
   // GL gives a bottom-to-top image, convert it to top-to-bottom
   uchar *tmp = new uchar[mByteWidth];
   uchar *p = baseAddress ;
-- 
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