[api-minor] Improve pdf reading in high contrast mode

- Use Canvas & CanvasText color when they don't have their default value
  as background and foreground colors.
- The colors used to draw (stroke/fill) in a pdf are replaced by the bg/fg
  ones according to their luminance.

test/driver.js

@@ -648,7 +648,8 @@ class Driver {
               renderForms = false,
               renderPrint = false,
               renderXfa = false,
-              annotationCanvasMap = null;
+              annotationCanvasMap = null,
+              pageColors = null;
 
             if (task.annotationStorage) {
               const entries = Object.entries(task.annotationStorage),
@@ -699,6 +700,7 @@ class Driver {
               renderForms = !!task.forms;
               renderPrint = !!task.print;
               renderXfa = !!task.enableXfa;
+              pageColors = task.pageColors || null;
 
               // Render the annotation layer if necessary.
               if (renderAnnotations || renderForms || renderXfa) {
@@ -746,6 +748,7 @@ class Driver {
               viewport,
               optionalContentConfigPromise: task.optionalContentConfigPromise,
               annotationCanvasMap,
+              pageColors,
               transform,
             };
             if (renderForms) {

test/test_manifest.json

@@ -60,6 +60,38 @@
        "enhance": true,
        "type": "text"
     },
+    {  "id": "tracemonkey-forced-colors-eq",
+      "file": "pdfs/tracemonkey.pdf",
+      "md5": "9a192d8b1a7dc652a19835f6f08098bd",
+      "rounds": 1,
+      "pageColors": {
+         "background": "black",
+         "foreground": "#00FF00"
+      },
+      "type": "eq"
+   },
+   {  "id": "tracemonkey-viewer-colors-eq",
+      "file": "pdfs/tracemonkey.pdf",
+      "md5": "9a192d8b1a7dc652a19835f6f08098bd",
+      "rounds": 1,
+      "pageColors": {
+         "background": "Canvas",
+         "foreground": "CanvasText"
+      },
+      "type": "eq",
+      "about": "Uses the same pageColors as the viewer."
+   },
+   {  "id": "tracemonkey-default-colors-eq",
+      "file": "pdfs/tracemonkey.pdf",
+      "md5": "9a192d8b1a7dc652a19835f6f08098bd",
+      "rounds": 1,
+      "pageColors": {
+         "background": "white",
+         "foreground": "black"
+      },
+      "type": "eq",
+      "about": "Uses the default colors."
+   },
     {  "id": "issue3925",
        "file": "pdfs/issue3925.pdf",
        "md5": "c5c895deecf7a7565393587e0d61be2b",