feat(core): add simple downscaling for bitmap copy ops

[no changelog]

core/embed/gfx/bitblt/gfx_bitblt_rgba8888.c

@@ -125,10 +125,10 @@ void gfx_rgba8888_copy_rgba8888(const gfx_bitblt_t* bb) {
 
     while (height-- > 0) {
       for (int x = 0; x < bb->width; x++) {
-        dst_ptr[x] = src_ptr[x];
+        dst_ptr[x] = src_ptr[x << bb->src_downscale];
       }
       dst_ptr += bb->dst_stride / sizeof(*dst_ptr);
-      src_ptr += bb->src_stride / sizeof(*src_ptr);
+      src_ptr += (bb->src_stride / sizeof(*src_ptr)) << bb->src_downscale;
     }
   }
 }

core/embed/gfx/bitblt/stm32/dma2d_bitblt.c

@@ -776,6 +776,10 @@ bool dma2d_rgba8888_copy_rgba8888(const gfx_bitblt_t* bb) {
     return false;
   }
 
+  if (bb->src_downscale > 0) {
+    return false;
+  }
+
   drv->handle.Init.ColorMode = DMA2D_OUTPUT_ARGB8888;
   drv->handle.Init.Mode = DMA2D_M2M_PFC;
   drv->handle.Init.OutputOffset = bb->dst_stride / sizeof(uint32_t) - bb->width;

core/embed/gfx/inc/gfx/gfx_bitblt.h

@@ -72,6 +72,9 @@ typedef struct {
   gfx_color_t src_bg;
   // Alpha value for fill operation (255 => normal fill, 0 => noop)
   uint8_t src_alpha;
+  // Downscaling for the source bitmap
+  // (0 => no downscaling, 1 => 1/2, 2 => 1/4, 3 => 1/8)
+  uint8_t src_downscale;
 
 } gfx_bitblt_t;
 

core/embed/rust/src/trezorhal/bitblt.rs

@@ -31,6 +31,7 @@ impl Default for ffi::gfx_bitblt_t {
             src_x: 0,
             src_y: 0,
             src_alpha: 255,
+            src_downscale: 0,
         }
     }
 }
@@ -128,6 +129,15 @@ impl ffi::gfx_bitblt_t {
             ..self
         }
     }
+
+    /// Sets the downscaling for the source bitmap.
+    /// (0 = no downscale, 1 = 1/2, 2 = 1/4, 3 = 1/8)
+    fn with_downscale(self, downscale: u8) -> Self {
+        Self {
+            src_downscale: downscale,
+            ..self
+        }
+    }
 }
 
 /// Rectangle filling operation.
@@ -250,16 +260,18 @@ impl<'a> BitBltCopy<'a> {
 
         // Clip with the bitmap top-left
         if r.x0 > r_dst.x0 {
-            offset.x += r.x0 - r_dst.x0;
+            offset.x += (r.x0 - r_dst.x0) << src.downscale;
         }
 
         if r.y0 > r_dst.y0 {
-            offset.y += r.y0 - r_dst.y0;
+            offset.y += (r.y0 - r_dst.y0) << src.downscale;
         }
 
         // Clip with the bitmap size
-        r.x1 = r.x1.min(r.x0 + src.size().x - offset.x);
-        r.y1 = r.y1.min(r.y0 + src.size().y - offset.y);
+        r.x1 =
+            r.x1.min(r.x0 + ((src.size().x - offset.x) >> src.downscale));
+        r.y1 =
+            r.y1.min(r.y0 + ((src.size().y - offset.y) >> src.downscale));
 
         if !r.is_empty() {
             Some(Self {
@@ -280,6 +292,7 @@ impl<'a> BitBltCopy<'a> {
                         .with_bg(src.bg_color)
                         .with_fg(src.fg_color)
                         .with_alpha(src.alpha)
+                        .with_downscale(src.downscale)
                 },
                 src,
             })

core/embed/rust/src/ui/shape/bitmap.rs

@@ -300,6 +300,7 @@ pub struct BitmapView<'a> {
     pub fg_color: Color,
     pub bg_color: Color,
     pub alpha: u8,
+    pub downscale: u8,
 }
 
 impl<'a> BitmapView<'a> {
@@ -311,6 +312,7 @@ impl<'a> BitmapView<'a> {
             fg_color: Color::black(),
             bg_color: Color::black(),
             alpha: 255,
+            downscale: 0,
         }
     }
 
@@ -337,6 +339,12 @@ impl<'a> BitmapView<'a> {
         Self { alpha, ..self }
     }
 
+    /// Builds a new structure with downscale set to the specified value
+    /// (0 means no downscale, 1 means 1/2, 2 means 1/4, etc.)
+    pub fn with_downscale(self, downscale: u8) -> Self {
+        Self { downscale, ..self }
+    }
+
     /// Returns the bitmap width and height in pixels
     pub fn size(&self) -> Offset {
         self.bitmap.size

core/embed/rust/src/ui/shape/jpeg.rs

@@ -108,8 +108,6 @@ impl<'a> Shape<'a> for JpegImage<'a> {
         let bounds = self.bounds();
         let clip = canvas.viewport().relative_clip(bounds).clip;
 
-        let vp = canvas.set_clip(clip);
-
         // Translate clip to JPEG relative coordinates
         let clip = clip.translate(-canvas.viewport().origin);
         let clip = clip.translate((-bounds.top_left()).into());
@@ -119,6 +117,13 @@ impl<'a> Shape<'a> for JpegImage<'a> {
 
         let mut jpegdec = unwrap!(JpegDecoder::new(self.jpeg));
         let _ = jpegdec.decode(&mut buff[..], &mut |slice_r, slice| {
+            let slice = slice.with_downscale(self.scale);
+            let slice_r = Rect {
+                x0: slice_r.x0 >> self.scale,
+                y0: slice_r.y0 >> self.scale,
+                x1: slice_r.x1 >> self.scale,
+                y1: slice_r.y1 >> self.scale,
+            };
             // Draw single slice
             canvas.draw_bitmap(slice_r.translate(bounds.top_left().into()), slice);
             // Return true if we are not done yet
@@ -136,8 +141,6 @@ impl<'a> Shape<'a> for JpegImage<'a> {
             // Blur the image
             canvas.blur_rect(clip, self.blur_radius, cache);
         }
-
-        canvas.set_viewport(vp);
     }
 
     // This is a little bit slower implementation suitable for ProgressiveRenderer