Added Fl_Shared_Image::scale(width, height) to support scaled image drawing (STR #3185).

Useful for printing, PostScript or PDF output, or retina displays.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10615 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

1 files changed, 64 insertions, 16 deletions

diff --git a/src/Fl_Image.cxx b/src/Fl_Image.cxx
index 3df1efde4..e4e88478e 100644
--- a/src/Fl_Image.cxx
+++ b/src/Fl_Image.cxx
@@ -3,7 +3,7 @@
 //
 // Image drawing code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2014 by Bill Spitzak and others.
+// Copyright 1998-2015 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -548,6 +548,21 @@ static int start(Fl_RGB_Image *img, int XP, int YP, int WP, int HP, int w, int h
   return 0;
 }
 
+/** Draws an Fl_RGB_Image scaled to width \p W & height \p H with top-left corner at \em X,Y
+ \return zero when the graphics driver doesn't implement scaled drawing, non-zero if it does implement it.
+ */
+int Fl_Graphics_Driver::draw_scaled(Fl_RGB_Image *img, int X, int Y, int W, int H) {
+  return 0;
+}
+
+/** Draws an Fl_Pixmap scaled to width \p W & height \p H with top-left corner at \em X,Y
+ \return zero when the graphics driver doesn't implement scaled drawing, non-zero if it does implement it.
+ */
+int Fl_Graphics_Driver::draw_scaled(Fl_Pixmap *img, int X, int Y, int W, int H) {
+  return 0;
+}
+
+
 #ifdef __APPLE__
 static void imgProviderReleaseData (void *info, const void *data, size_t size)
 {
@@ -612,7 +627,40 @@ void Fl_Quartz_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP,
   }
 }
 
+int Fl_Quartz_Graphics_Driver::draw_scaled(Fl_RGB_Image *img, int XP, int YP, int WP, int HP) {
+  int X, Y, W, H;
+  fl_clip_box(XP,YP,WP,HP,X,Y,W,H); // X,Y,W,H will give the unclipped area of XP,YP,WP,HP
+  if (W == 0 || H == 0) return 1;
+  fl_push_no_clip(); // remove the FLTK clip that can't be rescaled
+  CGContextSaveGState(fl_gc);
+  CGContextClipToRect(fl_gc, CGRectMake(X, Y, W, H)); // this clip path will be rescaled & translated
+  CGContextTranslateCTM(fl_gc, XP, YP);
+  CGContextScaleCTM(fl_gc, float(WP)/img->w(), float(HP)/img->h());
+  draw(img, 0, 0, img->w(), img->h(), 0, 0);
+  CGContextRestoreGState(fl_gc);
+  fl_pop_clip(); // restore FLTK's clip
+  return 1;
+}
+
 #elif defined(WIN32)
+static Fl_Offscreen build_id(Fl_RGB_Image *img, void **pmask)
+{
+  Fl_Offscreen offs = fl_create_offscreen(img->w(), img->h());
+  if ((img->d() == 2 || img->d() == 4) && fl_can_do_alpha_blending()) {
+    fl_begin_offscreen(offs);
+    fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d()|FL_IMAGE_WITH_ALPHA, img->ld());
+    fl_end_offscreen();
+  } else {
+    fl_begin_offscreen(offs);
+    fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d(), img->ld());
+    fl_end_offscreen();
+    if (img->d() == 2 || img->d() == 4) {
+      *pmask = fl_create_alphamask(img->w(), img->h(), img->d(), img->ld(), img->array);
+    }
+  }
+  return offs;
+}
+
 void Fl_GDI_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, int HP, int cx, int cy) {
   int X, Y, W, H;
   // Don't draw an empty image...
@@ -623,21 +671,7 @@ void Fl_GDI_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, int
   if (start(img, XP, YP, WP, HP, img->w(), img->h(), cx, cy, X, Y, W, H)) {
     return;
   }
-  if (!img->id_) {
-    img->id_ = fl_create_offscreen(img->w(), img->h());
-    if ((img->d() == 2 || img->d() == 4) && fl_can_do_alpha_blending()) {
-      fl_begin_offscreen((Fl_Offscreen)img->id_);
-      fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d()|FL_IMAGE_WITH_ALPHA, img->ld());
-      fl_end_offscreen();
-    } else {
-      fl_begin_offscreen((Fl_Offscreen)img->id_);
-      fl_draw_image(img->array, 0, 0, img->w(), img->h(), img->d(), img->ld());
-      fl_end_offscreen();
-      if (img->d() == 2 || img->d() == 4) {
-        img->mask_ = fl_create_alphamask(img->w(), img->h(), img->d(), img->ld(), img->array);
-      }
-    }
-  }
+  if (!img->id_) img->id_ = build_id(img, &(img->mask_));
   if (img->mask_) {
     HDC new_gc = CreateCompatibleDC(fl_gc);
     int save = SaveDC(new_gc);
@@ -654,6 +688,20 @@ void Fl_GDI_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, int
   }
 }
 
+int Fl_GDI_Printer_Graphics_Driver::draw_scaled(Fl_RGB_Image *img, int XP, int YP, int WP, int HP) {
+  XFORM old_tr, tr;
+  GetWorldTransform(fl_gc, &old_tr); // storing old transform
+  tr.eM11 = float(WP)/float(img->w());
+  tr.eM22 = float(HP)/float(img->h());
+  tr.eM12 = tr.eM21 = 0;
+  tr.eDx =  XP;
+  tr.eDy =  YP;
+  ModifyWorldTransform(fl_gc, &tr, MWT_LEFTMULTIPLY);
+  Fl_GDI_Graphics_Driver::draw(img, 0, 0, img->w(), img->h(), 0, 0);
+  SetWorldTransform(fl_gc, &old_tr);
+return 1;
+}
+
 #else
 void Fl_Xlib_Graphics_Driver::draw(Fl_RGB_Image *img, int XP, int YP, int WP, int HP, int cx, int cy) {
   int X, Y, W, H;