From 4f894e4745280958e1e4a08f4e49bd94abb5ea36 Mon Sep 17 00:00:00 2001
From: ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
Date: Sat, 25 Nov 2023 12:09:54 +0100
Subject: Cairo graphics driver: Improve drawing of Fl_Pixmap and Fl_Bitmap

Previously, these objects were drawn slightly blurred on HighDPI.
This commit has them resized to the pixel size of the area where
they are being drawn and then drawn.
---
 src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx | 82 +++++++++++++++-----------
 1 file changed, 49 insertions(+), 33 deletions(-)

(limited to 'src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx')

diff --git a/src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx b/src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx
index 37473f48c..be189f7bf 100644
--- a/src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx
+++ b/src/drivers/Cairo/Fl_Cairo_Graphics_Driver.cxx
@@ -106,6 +106,7 @@ Fl_Cairo_Graphics_Driver::Fl_Cairo_Graphics_Driver() : Fl_Graphics_Driver() {
   linestyle_ = FL_SOLID;
   clip_ = NULL;
   scale_x = scale_y = 1;
+  wld_scale = 1;
   angle = 0;
   left_margin = top_margin = 0;
   needs_commit_tag_ = NULL;
@@ -892,6 +893,10 @@ void Fl_Cairo_Graphics_Driver::cache(Fl_RGB_Image *rgb) {
   cairo_pattern_t *pat = cairo_pattern_create_for_surface(surf);
   cairo_surface_destroy(surf);
   *Fl_Graphics_Driver::id(rgb) = (fl_uintptr_t)pat;
+  int *pw, *ph;
+  cache_w_h(rgb, pw, ph);
+  *pw = rgb->data_w();
+  *ph = rgb->data_h();
 }
 
 
@@ -904,21 +909,27 @@ void Fl_Cairo_Graphics_Driver::uncache(Fl_RGB_Image *img, fl_uintptr_t &id_, fl_
 }
 
 
-void Fl_Cairo_Graphics_Driver::draw_bitmap(Fl_Bitmap *bm,int XP, int YP, int WP, int HP, int cx, int cy) {
-  int X, Y, W, H;
+void Fl_Cairo_Graphics_Driver::draw_fixed(Fl_Bitmap *bm,int XP, int YP, int WP, int HP, 
+                                          int cx, int cy) {
+  cairo_pattern_t *pat = NULL;
+  float s = wld_scale * scale();
+  XP = Fl_Scalable_Graphics_Driver::floor(XP, s);
+  YP = Fl_Scalable_Graphics_Driver::floor(YP, s);
+  cache_size(bm, WP, HP);
+  cx *= s; cy *= s;
+  cairo_matrix_t matrix; // temporarily remove scaling
+  cairo_get_matrix(cairo_, &matrix);
+  cairo_translate(cairo_, -0.5, -0.5);
+  cairo_scale(cairo_, 1./s, 1/s);
+  cairo_translate(cairo_, 0.5, 0.5);
   if (!bm->array) {
     draw_empty(bm, XP, YP);
-    return;
-  }
-  if (start_image(bm, XP,YP,WP,HP,cx,cy,X,Y,W,H)) return;
-  cairo_pattern_t *pat = (cairo_pattern_t*)*Fl_Graphics_Driver::id(bm);
-  if (!pat) {
-    cache(bm);
+  } else {
     pat = (cairo_pattern_t*)*Fl_Graphics_Driver::id(bm);
+    color(color());
+    draw_cached_pattern_(bm, pat, XP, YP, WP, HP, cx, cy);
   }
-  if (pat) {
-    draw_cached_pattern_(bm, pat, X, Y, W, H, cx, cy);
-  }
+  cairo_set_matrix(cairo_, &matrix);
 }
 
 
@@ -977,25 +988,34 @@ void Fl_Cairo_Graphics_Driver::cache(Fl_Bitmap *bm) {
   (void)cairo_surface_set_user_data(surf, &data_key_for_surface, BGRA, dealloc_surface_data);
   cairo_surface_destroy(surf);
   *Fl_Graphics_Driver::id(bm) = (fl_uintptr_t)pattern;
-}
-
-
-void Fl_Cairo_Graphics_Driver::draw_pixmap(Fl_Pixmap *pxm,int XP, int YP, int WP, int HP, int cx, int cy) {
-  int X, Y, W, H;
+  int *pw, *ph;
+  cache_w_h(bm, pw, ph);
+  *pw = bm->data_w();
+  *ph = bm->data_h();
+}
+
+
+void Fl_Cairo_Graphics_Driver::draw_fixed(Fl_Pixmap *pxm,int XP, int YP, int WP, int HP, 
+                                          int cx, int cy) {
+  cairo_pattern_t *pat = NULL;
+  float s = wld_scale * scale();
+  XP = Fl_Scalable_Graphics_Driver::floor(XP, s);
+  YP = Fl_Scalable_Graphics_Driver::floor(YP, s);
+  cache_size(pxm, WP, HP);
+  cx *= s; cy *= s;
+  cairo_matrix_t matrix; // temporarily remove scaling
+  cairo_get_matrix(cairo_, &matrix);
+  cairo_translate(cairo_, -0.5, -0.5);
+  cairo_scale(cairo_, 1/s, 1/s);
+  cairo_translate(cairo_, 0.5, 0.5);
   // Don't draw an empty image...
   if (!pxm->data() || !pxm->w()) {
     Fl_Graphics_Driver::draw_empty(pxm, XP, YP);
-    return;
-  }
-  if (start_image(pxm, XP, YP, WP, HP, cx, cy, X, Y, W, H)) {
-    return;
-  }
-  cairo_pattern_t *pat = (cairo_pattern_t*)*Fl_Graphics_Driver::id(pxm);
-  if (!pat) {
-    cache(pxm);
+  } else {
     pat = (cairo_pattern_t*)*Fl_Graphics_Driver::id(pxm);
+    draw_cached_pattern_(pxm, pat, XP, YP, WP, HP, cx, cy);
   }
-  draw_cached_pattern_(pxm, pat, X, Y, W, H, cx, cy);
+  cairo_set_matrix(cairo_, &matrix);
 }
 
 
@@ -1005,6 +1025,10 @@ void Fl_Cairo_Graphics_Driver::cache(Fl_Pixmap *pxm) {
   *Fl_Graphics_Driver::id(pxm) = *Fl_Graphics_Driver::id(rgb);
   *Fl_Graphics_Driver::id(rgb) = 0;
   delete rgb;
+  int *pw, *ph;
+  cache_w_h(pxm, pw, ph);
+  *pw = pxm->data_w();
+  *ph = pxm->data_h();
 }
 
 
@@ -1438,14 +1462,6 @@ void Fl_Cairo_Graphics_Driver::restore_clip() {
 }
 
 
-void Fl_Cairo_Graphics_Driver::cache_size(Fl_Image *unused, int &width, int &height) {
-  cairo_matrix_t matrix;
-  cairo_get_matrix(cairo_, &matrix);
-  width *= matrix.xx;
-  height *= matrix.xx;
-}
-
-
 char Fl_Cairo_Graphics_Driver::can_do_alpha_blending() {
   return 1;
 }
-- 
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