s390x test failure

[bastien-roucaries]

From debian on s390:

 1) Canvas
       Context2d#createPattern(Canvas).setTransform():

      AssertionError [ERR_ASSERTION]: The expression evaluated to a falsy value:

  assert.ok(r==clr && g==clr && b==clr && a==255)

      + expected - actual

      -false
      +true
      
      at /build/reproducible-path/node-canvas-3.2.3+dfsg/test/canvas.test.js:1951:16
      at eachPixel (test/canvas.test.js:1931:11)
      at isCheckerboard (test/canvas.test.js:1949:7)
      at /build/reproducible-path/node-canvas-3.2.3+dfsg/test/canvas.test.js:1970:7
      at Array.forEach (<anonymous>)
      at Context.<anonymous> (test/canvas.test.js:1966:32)
      at callFn (/usr/share/nodejs/mocha/lib/runnable.js:366:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:354:5)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  2) Canvas
       Context2d#putImageData()
         works for negative source values:

      AssertionError [ERR_ASSERTION]: Expected values to be loosely deep-equal:

Uint8ClampedArray(16) [
  212,
  170,
  85,
  6,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0
]

should loosely deep-equal

Uint8ClampedArray(16) [
  4,
  5,
  6,
  255,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0,
  0
]
      + expected - actual

      -{"0":212,"1":170,"2":85,"3":6,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0,"13":0,"14":0,"15":0}
      +{"0":4,"1":5,"2":6,"3":255,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0,"13":0,"14":0,"15":0}
      
      at Context.<anonymous> (test/canvas.test.js:2102:14)
      at callFn (/usr/share/nodejs/mocha/lib/runnable.js:366:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:354:5)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  3) Canvas
       Context2d#putImageData()
         works, RGBA32:

      AssertionError [ERR_ASSERTION]: 0 == 255
      + expected - actual

      -0
      +255
      
      at Context.<anonymous> (test/canvas.test.js:2119:14)
      at callFn (/usr/share/nodejs/mocha/lib/runnable.js:366:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:354:5)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  4) Canvas
       Context2d#putImageData()
         works, RGB24/alpha:false:

      AssertionError [ERR_ASSERTION]: 0 == 255
      + expected - actual

      -0
      +255
      
      at Context.<anonymous> (test/canvas.test.js:2136:14)
      at callFn (/usr/share/nodejs/mocha/lib/runnable.js:366:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:354:5)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  5) Image
       supports BMP
         parses 1-bit image:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:359:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  6) Image
       supports BMP
         parses 4-bit image:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:372:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  7) Image
       supports BMP
         parses 24-bit image:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:395:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  8) Image
       supports BMP
         parses 32-bit image:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:65:7)
      at Context.<anonymous> (test/image.test.js:420:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  9) Image
       supports BMP
         parses minimal BMP:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:438:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  10) Image
       supports BMP
         properly handles negative height:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:457:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  11) Image
       supports BMP
         color palette:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:470:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

  12) Image
       supports BMP
         V3 header:
     Error: Error while processing file header - inconsistent file size
      at setSource (lib/image.js:95:13)
      at Image.set (lib/image.js:62:9)
      at Context.<anonymous> (test/image.test.js:483:15)
      at callFnAsync (/usr/share/nodejs/mocha/lib/runnable.js:394:21)
      at Runnable.run (/usr/share/nodejs/mocha/lib/runnable.js:338:7)
      at Runner.runTest (/usr/share/nodejs/mocha/lib/runner.js:719:10)
      at /usr/share/nodejs/mocha/lib/runner.js:842:12
      at next (/usr/share/nodejs/mocha/lib/runner.js:634:14)
      at /usr/share/nodejs/mocha/lib/runner.js:644:7
      at next (/usr/share/nodejs/mocha/lib/runner.js:527:14)
      at Immediate._onImmediate (/usr/share/nodejs/mocha/lib/runner.js:612:5)
      at process.processImmediate (node:internal/timers:504:21)

Distribution: sid
Fail-Stage: build
Host Architecture: s390x
Install-Time: 48
Job: node-canvas_3.2.3+dfsg-1
Machine Architecture: s390x

[bastien-roucaries]

You likely forget to support big endian

[bastien-roucaries]

@chearon We could help here if needed on debian side

[chearon]

PRs are welcome!

[bastien-roucaries]

@chearon imagedata output in cairo native order, according to documentation it should output in rgba. Do you think it is a problem with the test or another problem ?

[chearon]

I haven't looked at the code for the tests yet, but there are places in node-canvas that use uint32_ts to represent RGBA with masking and shifting.

[bastien-roucaries]

Two patches (not pretty)

From: =?utf-8?q?Bastien_Roucari=C3=A8s?= <rouca@debian.org>
Date: Wed, 8 Jul 2026 11:31:00 +0200
Subject: Fix big endian

forwarded: https://github.com/Automattic/node-canvas/issues/2599
---
 src/CanvasRenderingContext2d.cc | 159 +++++++++++++++++++++++++---------------
 1 file changed, 99 insertions(+), 60 deletions(-)

diff --git a/src/CanvasRenderingContext2d.cc b/src/CanvasRenderingContext2d.cc
index 9c54820..2cc8787 100644
--- a/src/CanvasRenderingContext2d.cc
+++ b/src/CanvasRenderingContext2d.cc
@@ -20,6 +20,9 @@
 #include "Util.h"
 #include <vector>
 
+#define _BSD_SOURCE
+#include <endian.h>
+
 /*
  * Rectangle arg assertions.
  */
@@ -35,6 +38,39 @@
 
 constexpr double twoPi = M_PI * 2.;
 
+union PixelRGBA32 {
+    uint32_t value;   // packed 32‑bit pixel
+
+    struct {
+        uint8_t r;
+        uint8_t g;
+        uint8_t b;
+        uint8_t a;
+    } rgba;
+};
+
+union PixelARGB32 {
+    uint32_t value;   // packed 32‑bit pixel
+
+    struct {
+        uint8_t a;
+        uint8_t r;
+        uint8_t g;
+        uint8_t b;
+    } rgba;
+};
+
+
+static inline uint32_t load32(const void* p) {
+    uint32_t v;
+    std::memcpy(&v, p, sizeof(v));
+    return v;
+}
+
+static inline void store32(void* p, uint32_t v) {
+    std::memcpy(p, &v, sizeof(v));
+}
+
 /*
  * Simple helper macro for a rather verbose function call.
  */
@@ -840,7 +876,9 @@ Context2d::PutImageData(const Napi::CallbackInfo& info) {
 
   int dstStride = canvas()->stride();
   int Bpp = dstStride / canvas()->getWidth();
-  int srcStride = Bpp * imageData->width();
+  int imWidth = imageData->width();
+  int imHeight = imageData->height();
+  int srcStride = Bpp * imWidth;
 
   int64_t sx = 0
     , sy = 0
@@ -854,8 +892,8 @@ Context2d::PutImageData(const Napi::CallbackInfo& info) {
   switch (info.Length()) {
     // imageData, dx, dy
     case 3:
-      sw = imageData->width();
-      sh = imageData->height();
+      sw = imWidth;
+      sh = imHeight;
       break;
     // imageData, dx, dy, sx, sy, sw, sh
     case 7:
@@ -895,37 +933,35 @@ Context2d::PutImageData(const Napi::CallbackInfo& info) {
   switch (canvas()->getFormat()) {
   case CAIRO_FORMAT_ARGB32: {
     src += sy * srcStride + sx * 4;
-    dst += dstStride * dy + 4 * dx;
+    dst += dstStride * dy + sizeof(uint32_t) * dx;
+    PixelRGBA32 pixelsrc;
+    PixelARGB32 pixeldst;
     for (int y = 0; y < rows; ++y) {
-      uint8_t *dstRow = dst;
       uint8_t *srcRow = src;
+      uint32_t *dstRow = ((uint32_t *) dst);
       for (int x = 0; x < cols; ++x) {
-        // rgba
-        uint8_t r = *srcRow++;
-        uint8_t g = *srcRow++;
-        uint8_t b = *srcRow++;
-        uint8_t a = *srcRow++;
-
+        pixelsrc.rgba.r = *srcRow++;
+        pixelsrc.rgba.g = *srcRow++;
+        pixelsrc.rgba.b = *srcRow++;
+        pixelsrc.rgba.a = *srcRow++;
         // argb
         // performance optimization: fully transparent/opaque pixels can be
         // processed more efficiently.
-        if (a == 0) {
-          *dstRow++ = 0;
-          *dstRow++ = 0;
-          *dstRow++ = 0;
-          *dstRow++ = 0;
-        } else if (a == 255) {
-          *dstRow++ = b;
-          *dstRow++ = g;
-          *dstRow++ = r;
-          *dstRow++ = a;
+        if (pixelsrc.rgba.a == 0) {
+          pixeldst.rgba.a = pixeldst.rgba.r = pixeldst.rgba.g = pixeldst.rgba.b = 0;
+        } else if (pixelsrc.rgba.a == 255) {
+          pixeldst.rgba.a = pixelsrc.rgba.a;
+          pixeldst.rgba.r = pixelsrc.rgba.r;
+          pixeldst.rgba.b = pixelsrc.rgba.b;
+          pixeldst.rgba.g = pixelsrc.rgba.g;
         } else {
-          float alpha = (float)a / 255;
-          *dstRow++ = b * alpha;
-          *dstRow++ = g * alpha;
-          *dstRow++ = r * alpha;
-          *dstRow++ = a;
+          pixeldst.rgba.a = pixelsrc.rgba.a;
+          float alpha = (float)pixeldst.rgba.a / 255;
+          pixeldst.rgba.r = pixelsrc.rgba.r * alpha;
+          pixeldst.rgba.b = pixelsrc.rgba.b * alpha;
+          pixeldst.rgba.g = pixelsrc.rgba.g * alpha;
         }
+        store32(dstRow++, be32toh(pixeldst.value));
       }
       dst += dstStride;
       src += srcStride;
@@ -934,22 +970,27 @@ Context2d::PutImageData(const Napi::CallbackInfo& info) {
   }
   case CAIRO_FORMAT_RGB24: {
     src += sy * srcStride + sx * 4;
-    dst += dstStride * dy + 4 * dx;
+    dst += dstStride * dy + sizeof(uint32_t) * dx;
+    PixelRGBA32 pixelsrc;
+    PixelARGB32 pixeldst;
     for (int y = 0; y < rows; ++y) {
       uint8_t *dstRow = dst;
       uint8_t *srcRow = src;
       for (int x = 0; x < cols; ++x) {
         // rgba
-        uint8_t r = *srcRow++;
-        uint8_t g = *srcRow++;
-        uint8_t b = *srcRow++;
+        pixelsrc.rgba.r = *srcRow++;
+        pixelsrc.rgba.g = *srcRow++;
+        pixelsrc.rgba.b = *srcRow++;
+        pixelsrc.rgba.a = 255;
         srcRow++;
 
         // argb
-        *dstRow++ = b;
-        *dstRow++ = g;
-        *dstRow++ = r;
-        *dstRow++ = 255;
+        pixeldst.rgba.a = pixelsrc.rgba.a;
+        pixeldst.rgba.r = pixelsrc.rgba.r;
+        pixeldst.rgba.b = pixelsrc.rgba.b;
+        pixeldst.rgba.g = pixelsrc.rgba.g;
+
+        store32(dstRow++, be32toh(pixeldst.value));
       }
       dst += dstStride;
       src += srcStride;
@@ -1121,31 +1162,32 @@ Context2d::GetImageData(const Napi::CallbackInfo& info) {
     dst += oy * dstStride + ox * 4;
     // Rearrange alpha (argb -> rgba), undo alpha pre-multiplication,
     // and store in big-endian format
+    PixelARGB32 pixelsrc;
     for (int y = 0; y < ch; ++y) {
       uint32_t *row = (uint32_t *)(src + srcStride * (y + sy));
       for (int x = 0; x < cw; ++x) {
-        int bx = x * 4;
-        uint32_t *pixel = row + x + sx;
-        uint8_t a = *pixel >> 24;
-        uint8_t r = *pixel >> 16;
-        uint8_t g = *pixel >> 8;
-        uint8_t b = *pixel;
-        dst[bx + 3] = a;
-
+        int bx = x * sizeof(uint32_t);
+        pixelsrc.value = htobe32(load32(row + x + sx));
         // Performance optimization: fully transparent/opaque pixels can be
         // processed more efficiently.
-        if (a == 0 || a == 255) {
-          dst[bx + 0] = r;
-          dst[bx + 1] = g;
-          dst[bx + 2] = b;
+        if (pixelsrc.rgba.a == 0) {
+          dst[bx + 0] = 0;
+          dst[bx + 1] = 0;
+          dst[bx + 2] = 0;
+          dst[bx + 3] = 0;
+        } else if (pixelsrc.rgba.a == 255) {
+          dst[bx + 0] = pixelsrc.rgba.r;
+          dst[bx + 1] = pixelsrc.rgba.g;
+          dst[bx + 2]  = pixelsrc.rgba.b;
+          dst[bx + 3] = pixelsrc.rgba.a;
         } else {
           // Undo alpha pre-multiplication
-          float alphaR = (float)255 / a;
-          dst[bx + 0] = (int)((float)r * alphaR);
-          dst[bx + 1] = (int)((float)g * alphaR);
-          dst[bx + 2] = (int)((float)b * alphaR);
+          float alphaR = (float)255 / pixelsrc.rgba.a;
+          dst[bx + 0] = (int)((float)pixelsrc.rgba.r * alphaR);
+          dst[bx + 1] = (int)((float)pixelsrc.rgba.g * alphaR);
+          dst[bx + 2] = (int)((float)pixelsrc.rgba.b * alphaR);
+          dst[bx + 3] = pixelsrc.rgba.a;
         }
-
       }
       dst += dstStride;
     }
@@ -1153,19 +1195,16 @@ Context2d::GetImageData(const Napi::CallbackInfo& info) {
   }
   case CAIRO_FORMAT_RGB24: {
     dst += oy * dstStride + ox * 4;
+    PixelARGB32 pixelsrc;
   // Rearrange alpha (argb -> rgba) and store in big-endian format
     for (int y = 0; y < ch; ++y) {
     uint32_t *row = (uint32_t *)(src + srcStride * (y + sy));
     for (int x = 0; x < cw; ++x) {
-      int bx = x * 4;
-      uint32_t *pixel = row + x + sx;
-      uint8_t r = *pixel >> 16;
-      uint8_t g = *pixel >> 8;
-      uint8_t b = *pixel;
-
-      dst[bx + 0] = r;
-      dst[bx + 1] = g;
-      dst[bx + 2] = b;
+      int bx = x * sizeof(uint32_t);
+      pixelsrc.value = htobe32(load32(row + x + sx));
+      dst[bx + 0] = pixelsrc.rgba.r;
+      dst[bx + 1] = pixelsrc.rgba.g;
+      dst[bx + 2]  = pixelsrc.rgba.b;
       dst[bx + 3] = 255;
     }
     dst += dstStride;

[bastien-roucaries]

patch here (not pretty need to be improved)

From: =?utf-8?q?Bastien_Roucari=C3=A8s?= <rouca@debian.org>
Date: Wed, 8 Jul 2026 16:24:21 +0200
Subject: Fix endian of bmparser

forwarded: https://github.com/Automattic/node-canvas/issues/2599
---
 src/Image.cc         | 41 +++++++++++++++++++++++++++++++++++------
 src/bmp/BMPParser.cc | 50 +++++++++++++++++++++++++++++++++++---------------
 2 files changed, 70 insertions(+), 21 deletions(-)

diff --git a/src/Image.cc b/src/Image.cc
index 06dd564..724445f 100644
--- a/src/Image.cc
+++ b/src/Image.cc
@@ -11,11 +11,30 @@
 #include <node_buffer.h>
 #include <sys/stat.h>
 
+#include <array>
+#include <bit>
+
 /* Cairo limit:
   * https://lists.cairographics.org/archives/cairo/2010-December/021422.html
   */
 static constexpr int canvas_max_side = (1 << 15) - 1;
 
+template<std::endian E = std::endian::native>
+constexpr auto pixFmt() {
+    std::array<uint8_t,5> fmt{};
+
+    if constexpr (E == std::endian::little) {
+        // Cairo ARGB32 → BGRA bytes
+        fmt = {2, 1, 0, 3, 1};
+    } else {
+        // Cairo ARGB32 → ARGB bytes
+        fmt = {3, 0, 1, 2, 1};
+    }
+
+    return fmt;
+}
+
+
 #ifdef HAVE_GIF
 typedef struct {
   uint8_t *buf;
@@ -1576,8 +1595,8 @@ cairo_status_t Image::loadBMPFromBuffer(uint8_t *buf, unsigned len){
   BMPParser::Parser parser;
 
   // Reversed ARGB32 with pre-multiplied alpha
-  uint8_t pixFmt[5] = {2, 1, 0, 3, 1};
-  parser.parse(buf, len, pixFmt);
+  auto fmt = pixFmt<>();
+  parser.parse(buf, len, fmt.data());
 
   if (parser.getStatus() != BMPParser::Status::OK) {
     errorInfo.reset();
@@ -1587,20 +1606,30 @@ cairo_status_t Image::loadBMPFromBuffer(uint8_t *buf, unsigned len){
 
   width = naturalWidth = parser.getWidth();
   height = naturalHeight = parser.getHeight();
+  uint32_t src_stride = width * sizeof(uint32_t);
   uint8_t *data = parser.getImgd();
 
-  _surface = cairo_image_surface_create_for_data(
-    data,
+  int dst_stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width);
+  _surface = cairo_image_surface_create(
     CAIRO_FORMAT_ARGB32,
     width,
-    height,
-    cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width)
+    height
   );
 
   // No need to delete the data
   cairo_status_t status = cairo_surface_status(_surface);
   if (status) return status;
 
+  uint8_t *dst = cairo_image_surface_get_data(_surface);
+  for (int y = 0; y < height; y++) {
+     memcpy(
+       dst + y * dst_stride,
+       data + y * src_stride,
+       src_stride
+     );
+   }
+
+  cairo_surface_mark_dirty(_surface);
   _data = data;
   parser.clearImgd();
 
diff --git a/src/bmp/BMPParser.cc b/src/bmp/BMPParser.cc
index 9058be8..000eaa5 100644
--- a/src/bmp/BMPParser.cc
+++ b/src/bmp/BMPParser.cc
@@ -2,6 +2,12 @@
 
 #include <cassert>
 #include <cstring>
+
+#include <bit>
+#include <cstdint>
+#include <cstring>
+
+
 
 using namespace std;
 using namespace BMPParser;
@@ -382,21 +388,35 @@ string Parser::getErrMsg() const{
   return "Error while processing " + getOp() + " - " + err;
 }
 
-template <typename T, bool check> inline T Parser::get(){
-  if(check)
-    CHECK_OVERRUN(ptr, sizeof(T), T);
-  T val;
-  std::memcpy(&val, ptr, sizeof(T));
-  ptr += sizeof(T);
-  return val;
-}
-
-template <typename T, bool check> inline T Parser::get(uint8_t* pointer){
-  if(check)
-    CHECK_OVERRUN(pointer, sizeof(T), T);
-  T val = *(T*)pointer;
-  return val;
-}
+
+template <typename T, bool check>
+inline T Parser::get() {
+    if (check)
+        CHECK_OVERRUN(ptr, sizeof(T), T);
+
+    T val;
+    std::memcpy(&val, ptr, sizeof(T));
+    ptr += sizeof(T);
+
+    if constexpr (sizeof(T) > 1 && std::endian::native == std::endian::big)
+        val = std::byteswap(val);
+    return val;
+}
+
+template <typename T, bool check>
+inline T Parser::get(uint8_t* pointer) {
+    if (check)
+        CHECK_OVERRUN(pointer, sizeof(T), T);
+
+    T val;
+    std::memcpy(&val, pointer, sizeof(T));
+
+    if constexpr (sizeof(T) > 1 && std::endian::native == std::endian::big)
+        val = std::byteswap(val);
+
+    return val;
+}
+
 
 string Parser::getStr(int size, bool reverse){
   CHECK_OVERRUN(ptr, size, string);

[bastien-roucaries]

Source here:
https://salsa.debian.org/js-team/node-canvas/-/tree/master/debian/patches?ref_type=heads

[chearon]

Thanks for the patches, they look good. endian.h seems to be Unix-specific, so that has to be figured out. I don't think Windows or macOS can run on any big-endian CPUs, so I think I could just read/write in little-endian in that case.