New member function Fl_Image_Surface::mask(Fl_RGB_Image*)

2 files changed, 134 insertions, 1 deletions

diff --git a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.H b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.H
index ab702840d..382daf886 100644
--- a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.H
+++ b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.H
@@ -1,7 +1,7 @@
 //
 // Draw-to-image code for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 2022 by Bill Spitzak and others.
+// Copyright 2022-2023 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
@@ -32,8 +32,19 @@ public:
   void translate(int x, int y) FL_OVERRIDE;
   void untranslate() FL_OVERRIDE;
   Fl_RGB_Image *image() FL_OVERRIDE;
+  void mask(const Fl_RGB_Image *) FL_OVERRIDE;
 #if FLTK_USE_CAIRO
   cairo_t *cairo_;
+  struct shape_data_type {
+    double scale;
+    cairo_pattern_t *mask_pattern_;
+    cairo_t *bg_cr;
+  } *shape_data_;
+#else
+  struct shape_data_type {
+    Pixmap background;
+    Fl_RGB_Image* mask;
+  } *shape_data_;
 #endif
 };
 
diff --git a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
index bcaf7d46a..87e55b417 100644
--- a/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
+++ b/src/drivers/Xlib/Fl_Xlib_Image_Surface_Driver.cxx
@@ -17,6 +17,7 @@
 #include <FL/platform.H>
 #include "Fl_Xlib_Image_Surface_Driver.H"
 #include "../../Fl_Screen_Driver.H"
+#include <stdlib.h>
 #if FLTK_USE_CAIRO
 #  include <cairo-xlib.h>
 #  include "../Cairo/Fl_X11_Cairo_Graphics_Driver.H"
@@ -37,6 +38,7 @@ Fl_Xlib_Image_Surface_Driver::Fl_Xlib_Image_Surface_Driver(int w, int h, int hig
     }
     offscreen = (Fl_Offscreen)XCreatePixmap(fl_display, RootWindow(fl_display, fl_screen), w, h, fl_visual->depth);
   }
+  shape_data_ = NULL;
 #if FLTK_USE_CAIRO
   driver(new Fl_X11_Cairo_Graphics_Driver());
   cairo_surface_t *s = cairo_xlib_surface_create(fl_display, offscreen, fl_visual->visual, w, h);
@@ -52,7 +54,24 @@ Fl_Xlib_Image_Surface_Driver::Fl_Xlib_Image_Surface_Driver(int w, int h, int hig
 
 Fl_Xlib_Image_Surface_Driver::~Fl_Xlib_Image_Surface_Driver() {
 #if FLTK_USE_CAIRO
+  if (shape_data_) {
+    cairo_surface_t *surf;
+    cairo_pattern_get_surface(shape_data_->mask_pattern_, &surf);
+    unsigned char *bits = cairo_image_surface_get_data(surf);
+    cairo_pattern_destroy(shape_data_->mask_pattern_);
+    delete[] bits;
+    Pixmap p = cairo_xlib_surface_get_drawable(cairo_get_target(shape_data_->bg_cr));
+    XFreePixmap(fl_display, p);
+    cairo_destroy(shape_data_->bg_cr);
+    free(shape_data_);
+  }
   cairo_destroy(cairo_);
+#else
+  if (shape_data_) {
+    XFreePixmap(fl_display, shape_data_->background);
+    delete shape_data_->mask;
+    free(shape_data_);
+  }
 #endif
   if (offscreen && !external_offscreen) XFreePixmap(fl_display, (Pixmap)offscreen);
   delete driver();
@@ -84,14 +103,117 @@ void Fl_Xlib_Image_Surface_Driver::untranslate() {
 #endif
 }
 
+
 Fl_RGB_Image* Fl_Xlib_Image_Surface_Driver::image()
 {
+  if (shape_data_) {
+#if FLTK_USE_CAIRO
+    // draw above the secondary offscreen the main offscreen masked by mask_pattern_
+    cairo_t *c = ((Fl_Cairo_Graphics_Driver*)driver())->cr();
+    cairo_pattern_t *paint_pattern = cairo_pattern_create_for_surface(cairo_get_target(c));
+    cairo_set_source(shape_data_->bg_cr, paint_pattern);
+    cairo_mask(shape_data_->bg_cr, shape_data_->mask_pattern_);
+    cairo_pattern_destroy(paint_pattern);
+    // copy secondary offscreen to the main offscreen
+    cairo_pattern_t *pat = cairo_pattern_create_for_surface(cairo_get_target(shape_data_->bg_cr));
+    cairo_scale(c, shape_data_->scale, shape_data_->scale);
+    cairo_set_source(c, pat),
+    cairo_paint(c);
+    cairo_pattern_destroy(pat);
+    // delete secondary offscreen
+    cairo_surface_t *surf;
+    cairo_pattern_get_surface(shape_data_->mask_pattern_, &surf);
+    unsigned char *bits = cairo_image_surface_get_data(surf);
+    cairo_pattern_destroy(shape_data_->mask_pattern_);
+    delete[] bits;
+    Pixmap p = cairo_xlib_surface_get_drawable(cairo_get_target(shape_data_->bg_cr));
+    XFreePixmap(fl_display, p);
+    cairo_destroy(shape_data_->bg_cr);
+#else // !FLTK_USE_CAIRO
+  // draw the main offscreen masked by shape_data_->mask above the background offscreen
+    int w, h;
+    printable_rect(&w, &h);
+    Fl_RGB_Image *img_main = Fl::screen_driver()->read_win_rectangle(0, 0, w, h, 0);
+    fl_window = shape_data_->background; // temporary change
+    Fl_RGB_Image *img_background = Fl::screen_driver()->read_win_rectangle(0, 0, w, h, 0);
+    fl_window = offscreen;
+    Fl_Image_Surface_Driver::copy_with_mask(shape_data_->mask, 
+                                            (uchar*)img_background->array,
+                                            (uchar*)img_main->array,
+                                            3 * shape_data_->mask->w(), false);
+    delete img_main;
+  // copy background offscreen to main offscreen
+    float s = driver()->scale();
+    driver()->scale(1);
+    fl_draw_image(img_background->array, 0, 0,
+                  img_background->data_w(), img_background->data_h());
+    driver()->scale(s);
+    delete img_background;
+  // delete background offscreen
+    XFreePixmap(fl_display, shape_data_->background);
+    delete shape_data_->mask;
+#endif // FLTK_USE_CAIRO
+    free(shape_data_);
+    shape_data_ = NULL;
+}
   Fl_RGB_Image *image = Fl::screen_driver()->read_win_rectangle(0, 0, width, height, 0);
   return image;
 }
 
+
 void Fl_Xlib_Image_Surface_Driver::end_current()
 {
   fl_window = pre_window;
   Fl_Surface_Device::end_current();
 }
+
+
+#if FLTK_USE_CAIRO
+
+void Fl_Xlib_Image_Surface_Driver::mask(const Fl_RGB_Image *mask) {
+  bool using_copy = false;
+  shape_data_ =  (struct shape_data_type*)calloc(1, sizeof(struct shape_data_type));
+  int W, H;
+  cairo_t *c = ((Fl_Cairo_Graphics_Driver*)driver())->cr();
+  cairo_surface_t *c_surface = cairo_get_target(c);
+  W = cairo_xlib_surface_get_width(c_surface);
+  H = cairo_xlib_surface_get_height(c_surface);
+  if (W != mask->data_w() || H != mask->data_h()) {
+    Fl_RGB_Image *copy = (Fl_RGB_Image*)mask->copy(W, H);
+    mask = copy;
+    using_copy = true;
+  }
+  shape_data_->mask_pattern_ = Fl_Cairo_Graphics_Driver::calc_cairo_mask(mask);
+  //duplicate current offscreen content to new cairo_t* shape_data_->bg_cr
+  int width, height;
+  printable_rect(&width, &height);
+  Pixmap pxm = XCreatePixmap(fl_display, RootWindow(fl_display, fl_screen), W, H, fl_visual->depth);
+  cairo_surface_t *background = cairo_xlib_surface_create(fl_display, pxm, fl_visual->visual, W, H);
+  shape_data_->bg_cr = cairo_create(background);
+  cairo_surface_destroy(background);
+  cairo_surface_flush(c_surface);
+  cairo_pattern_t *pat = cairo_pattern_create_for_surface(c_surface);
+  cairo_set_source(shape_data_->bg_cr, pat),
+  cairo_paint(shape_data_->bg_cr);
+  cairo_pattern_destroy(pat);
+  shape_data_->scale = double(width) / W;
+  if (using_copy) delete mask;
+}
+
+#else
+
+void Fl_Xlib_Image_Surface_Driver::mask(const Fl_RGB_Image *mask) {
+  shape_data_ =  (struct shape_data_type*)calloc(1, sizeof(struct shape_data_type));
+  // get dimensions
+  int W, H;
+  Fl::screen_driver()->offscreen_size(offscreen, W, H);
+  // compute depth-1 mask
+  shape_data_->mask = Fl_Image_Surface_Driver::RGB3_to_RGB1(mask, W, H);
+
+  // duplicate current offscreen content to new, background offscreen
+  shape_data_->background = XCreatePixmap(fl_display, RootWindow(fl_display, fl_screen), W, H, fl_visual->depth);
+  driver()->restore_clip();
+  XCopyArea(fl_display, (Pixmap)offscreen, shape_data_->background, (GC)driver()->gc(), 0, 0, W, H,  0, 0);
+}
+
+#endif // FLTK_USE_CAIRO