#7992 Isolate PDF SMask

drawcontext.h

@@ -24,6 +24,7 @@ typedef struct DrawContext {
 	double gamma;
 	int offset_x;
 	int offset_y;
+    int isolate_smask;
 } DrawContext;
 
 #endif

ffi-cdecl/wrap-mupdf_cdecl.c

@@ -136,6 +136,7 @@ cdecl_func(fz_device_bgr)
 /* device, rendering */
 cdecl_func(mupdf_new_draw_device)
 cdecl_func(mupdf_new_bbox_device)
+cdecl_func(mupdf_new_isolated_smask_device)
 cdecl_func(mupdf_run_page)
 cdecl_func(fz_close_device)
 cdecl_func(fz_drop_device)

ffi/drawcontext.lua

@@ -13,6 +13,7 @@ typedef struct DrawContext {
 	double gamma;
 	int offset_x;
 	int offset_y;
+	int isolate_smask;
 } DrawContext;
 ]]
 
@@ -30,11 +31,13 @@ end
 function DC_mt.__index:getOffset() return self.offset_x, self.offset_y end
 function DC_mt.__index:setGamma(gamma) self.gamma = gamma end
 function DC_mt.__index:getGamma() return self.gamma end
+function DC_mt.__index:setIsolateSMask(isolate_smask) self.isolate_smask = isolate_smask end
+function DC_mt.__index:getIsolateSMask() return self.isolate_smask end
 
 local dctype = ffi.metatype("DrawContext", DC_mt)
 
-function DC.new(rotate, zoom, x, y, gamma)
-	return dctype(rotate or 0, zoom or 1.0, gamma or -1.0, x or 0, y or 0)
+function DC.new(rotate, zoom, x, y, gamma, isolate_smask)
+	return dctype(rotate or 0, zoom or 1.0, gamma or -1.0, x or 0, y or 0, isolate_smask or 0)
 end
 
 return DC

ffi/mupdf.lua

@@ -670,16 +670,29 @@ function page_mt.__index:getPageLinks()
     return links
 end
 
-local function run_page(page, pixmap, ctm)
+local function run_page(page, pixmap, ctm, isolate_smask)
     M.fz_clear_pixmap_with_value(page.ctx, pixmap, 0xff)
 
     local dev = W.mupdf_new_draw_device(page.ctx, nil, pixmap)
     if dev == nil then merror(page.ctx, "cannot create draw device") end
 
-    local ok = W.mupdf_run_page(page.ctx, page.page, dev, ctm, nil)
+    local ok = false
+    if isolate_smask then
+        local smask_dev = W.mupdf_new_isolated_smask_device(page.ctx, dev)
+        if smask_dev then
+            ok = W.mupdf_run_page(page.ctx, page.page, smask_dev, ctm, nil)
+            M.fz_close_device(page.ctx, smask_dev)
+            M.fz_drop_device(page.ctx, smask_dev)
+        end
+    end
+    if not ok then
+        ok = W.mupdf_run_page(page.ctx, page.page, dev, ctm, nil)
+    end
+
     M.fz_close_device(page.ctx, dev)
     M.fz_drop_device(page.ctx, dev)
-    if ok == nil then merror(page.ctx, "could not run page") end
+
+    if not ok then merror(page.ctx, "could not run page") end
 end
 --[[
 render page to blitbuffer
@@ -717,7 +730,7 @@ function page_mt.__index:draw_new(draw_context, width, height, offset_x, offset_
         self.ctx, colorspace, bbox, nil, self.doc.color and 1 or 0, ffi.cast("unsigned char*", bb.data))
     if pix == nil then merror(self.ctx, "cannot allocate pixmap") end
 
-    run_page(self, pix, ctm)
+    run_page(self, pix, ctm, draw_context.isolate_smask == 1)
 
     if draw_context.gamma >= 0.0 then
         M.fz_gamma_pixmap(self.ctx, pix, draw_context.gamma)
@@ -1087,7 +1100,7 @@ local function render_for_kopt(bmp, page, scale, bounds)
     local pix = W.mupdf_new_pixmap_with_bbox(page.ctx, colorspace, bbox, nil, 1)
     if pix == nil then merror(page.ctx, "could not allocate pixmap") end
 
-    run_page(page, pix, ctm)
+    run_page(page, pix, ctm, false)
 
     k2pdfopt.bmp_init(bmp)
 

ffi/mupdf_h.lua

@@ -248,6 +248,7 @@ fz_colorspace *fz_device_rgb(fz_context *);
 fz_colorspace *fz_device_bgr(fz_context *);
 fz_device *mupdf_new_draw_device(fz_context *, const fz_matrix *, fz_pixmap *);
 fz_device *mupdf_new_bbox_device(fz_context *, fz_rect *);
+fz_device *mupdf_new_isolated_smask_device(fz_context *, fz_device *);
 void *mupdf_run_page(fz_context *, fz_page *, fz_device *, const fz_matrix *, fz_cookie *);
 void fz_close_device(fz_context *, fz_device *);
 void fz_drop_device(fz_context *, fz_device *);

mupdf_utils.c

@@ -0,0 +1,26 @@
+#include "mupdf_utils.h"
+#include <mupdf/fitz.h>
+
+typedef struct
+{
+    fz_device super;
+    fz_device* default_device;
+} isolated_smask_device;
+
+static void smask_fill_image(fz_context* ctx, fz_device* dev, fz_image* img, fz_matrix ctm, float alpha, fz_color_params color_params)
+{
+    isolated_smask_device* smask_dev = (isolated_smask_device*)dev;
+    if (img->mask) {
+        float black[1] = { 0.f };
+        fz_fill_image_mask(ctx, smask_dev->default_device, img->mask, ctm,
+                           fz_device_gray(ctx), black, alpha, color_params);
+    }
+}
+
+fz_device *fz_new_isolated_smask_device(fz_context* ctx, fz_device* dev)
+{
+    isolated_smask_device* smask_dev = fz_new_derived_device(ctx, isolated_smask_device);
+    smask_dev->default_device = dev;
+    smask_dev->super.fill_image = smask_fill_image;
+    return (fz_device*)smask_dev;
+}

mupdf_utils.h

@@ -0,0 +1,15 @@
+#ifndef MUPDF_UTILS_H
+#define MUPDF_UTILS_H
+
+typedef struct fz_device fz_device;
+typedef struct fz_context fz_context;
+typedef struct fz_page fz_page;
+
+/**
+	Create a device to draw an isolated soft mask on a pixmap.
+
+	dev: Default draw device
+*/
+fz_device* fz_new_isolated_smask_device(fz_context* ctx, fz_device* dev);
+
+#endif

thirdparty/cmake_modules/koreader_targets.cmake

@@ -159,7 +159,7 @@ declare_koreader_target(
 declare_koreader_target(
     wrap-mupdf TYPE monolibtic
     DEPENDS mupdf::mupdf
-    SOURCES wrap-mupdf.c
+    SOURCES wrap-mupdf.c mupdf_utils.c
     VISIBILITY hidden
 )
 function(setup_wrap_mupdf)

wrap-mupdf.h

@@ -22,6 +22,7 @@
 #include <math.h>
 #include <mupdf/fitz.h>
 #include <mupdf/pdf.h>
+#include "mupdf_utils.h"
 
 // Symbol visibility
 #define DLL_PUBLIC __attribute__((visibility("default")))
@@ -114,6 +115,9 @@ MUPDF_WRAP(mupdf_new_bbox_device, fz_device*, NULL,
 MUPDF_WRAP(mupdf_new_draw_device, fz_device*, NULL,
     ret = fz_new_draw_device(ctx, transform ? *transform : fz_identity, dest),
     const fz_matrix *transform, fz_pixmap *dest)
+MUPDF_WRAP(mupdf_new_isolated_smask_device, fz_device*, NULL,
+    ret = fz_new_isolated_smask_device(ctx, dev),
+    fz_device *dev)
 MUPDF_WRAP(mupdf_run_page, void*, NULL,
     { fz_run_page(ctx, page, dev, *transform, cookie); ret = (void*) -1; },
     fz_page *page, fz_device *dev, const fz_matrix *transform, fz_cookie *cookie)