From 7abda5a59b8bccd59138ea49e5866041cc482b8a Mon Sep 17 00:00:00 2001
From: Manolo Gouy <Manolo>
Date: Wed, 27 Dec 2017 13:51:41 +0000
Subject: GUI rescaling under MacOS: fix Fl_Cocoa_Screen_Driver::read_image()
 when reading from scaled offscreen buffer

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.4@12609 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx       | 30 +++++++++++++++++-----
 .../Quartz/Fl_Quartz_Image_Surface_Driver.cxx      |  3 +++
 2 files changed, 27 insertions(+), 6 deletions(-)

(limited to 'src')

diff --git a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
index e4f86aa90..f03d399af 100644
--- a/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
+++ b/src/drivers/Cocoa/Fl_Cocoa_Screen_Driver.cxx
@@ -280,25 +280,34 @@ int Fl_Cocoa_Screen_Driver::compose(int &del) {
   return 1;
 }
 
-uchar *                                                 // O - Pixel buffer or NULL if failed
-Fl_Cocoa_Screen_Driver::read_image(uchar *p,		// I - Pixel buffer or NULL to allocate
+uchar *                                       // O - Pixel buffer or NULL if failed
+Fl_Cocoa_Screen_Driver::read_image(uchar *p,	// I - Pixel buffer or NULL to allocate
                                    int   x,		// I - Left position
                                    int   y,		// I - Top position
                                    int   w,		// I - Width of area to read
                                    int   h,		// I - Height of area to read
-                                   int   alpha) 	// I - Alpha value for image (0 for none)
+                                   int   alpha)// I - Alpha value for image (0 for none)
 {
   uchar *base;
   int rowBytes, delta;
+  float s = 1;
+  int ori_w = w, ori_h = h;
   if (fl_window == NULL) { // reading from an offscreen buffer
     CGContextRef src = (CGContextRef)Fl_Surface_Device::surface()->driver()->gc();  // get bitmap context
     base = (uchar *)CGBitmapContextGetData(src);  // get data
     if(!base) return NULL;
     int sw = CGBitmapContextGetWidth(src);
     int sh = CGBitmapContextGetHeight(src);
+    if( (sw - x < w) || (sh - y < h) )  return NULL;
     rowBytes = CGBitmapContextGetBytesPerRow(src);
     delta = CGBitmapContextGetBitsPerPixel(src)/8;
-    if( (sw - x < w) || (sh - y < h) )  return NULL;
+    Fl_Image_Surface *imgs = (Fl_Image_Surface*)Fl_Surface_Device::surface();
+    int fltk_w, fltk_h;
+    imgs->printable_rect(&fltk_w, &fltk_h);
+    s = sw / float(fltk_w);
+    x *= s; y *= s; w *= s; h *= s;
+    if (x + w > sw) w = sw - x;
+    if (y + h > sh) h = sh - y;
   }
   else { // reading from current window
     Fl_Cocoa_Window_Driver *d = Fl_Cocoa_Window_Driver::driver(Fl_Window::current());
@@ -313,7 +322,7 @@ Fl_Cocoa_Screen_Driver::read_image(uchar *p,		// I - Pixel buffer or NULL to all
   // Initialize the default colors/alpha in the whole image...
   memset(p, alpha, w * h * d);
   // Copy the image from the off-screen buffer to the memory buffer.
-  int           idx, idy;	// Current X & Y in image
+  int idx, idy;	// Current X & Y in image
   uchar *pdst, *psrc;
   for (idy = y, pdst = p; idy < h + y; idy ++) {
     for (idx = 0, psrc = base + idy * rowBytes + x * delta; idx < w; idx ++, psrc += delta, pdst += d) {
@@ -322,7 +331,16 @@ Fl_Cocoa_Screen_Driver::read_image(uchar *p,		// I - Pixel buffer or NULL to all
       pdst[2] = psrc[2];  // B
     }
   }
-  if(fl_window != NULL) delete[] base;
+  if (fl_window != NULL) delete[] base;
+  if (s != 1) {
+    Fl_RGB_Image *rgb = new Fl_RGB_Image(p, w, h, alpha ? 4 : 3);
+    rgb->alloc_array = 1;
+    Fl_RGB_Image *rgb2 = (Fl_RGB_Image*)rgb->copy(ori_w, ori_h);
+    rgb2->alloc_array = 0;
+    delete rgb;
+    p = (uchar*)rgb2->array;
+    delete rgb2;
+  }
   return p;
 }
 
diff --git a/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx b/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
index 573a5df8e..1702ca4ab 100644
--- a/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
+++ b/src/drivers/Quartz/Fl_Quartz_Image_Surface_Driver.cxx
@@ -104,7 +104,10 @@ Fl_RGB_Image* Fl_Quartz_Image_Surface_Driver::image()
   CGContextFlush(offscreen);
   int W = CGBitmapContextGetWidth(offscreen);
   int H = CGBitmapContextGetHeight(offscreen);
+  int save_w = width, save_h = height;
+  width = W; height = H;
   unsigned char *data = fl_read_image(NULL, 0, 0, W, H, 0);
+  width = save_w; height = save_h;
   Fl_RGB_Image *image = new Fl_RGB_Image(data, W, H);
   image->alloc_array = 1;
   return image;
-- 
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