From 23c1f33d3244772f4e1f9f5f8a507694f8f4b833 Mon Sep 17 00:00:00 2001
From: lashman <lashman@robotbrush.com>
Date: Fri, 6 Mar 2026 14:51:17 +0200
Subject: [PATCH] Support per-format conversion mapping in processing pipeline

Build FormatMapping when per-format overrides are set in the convert
step advanced options, falling back to SingleFormat when no overrides
are configured.
---
 pixstrip-gtk/src/app.rs | 46 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/pixstrip-gtk/src/app.rs b/pixstrip-gtk/src/app.rs
index 9f33ee3..5cc34b9 100644
--- a/pixstrip-gtk/src/app.rs
+++ b/pixstrip-gtk/src/app.rs
@@ -1147,8 +1147,50 @@ fn run_processing(_window: &adw::ApplicationWindow, ui: &WizardUi) {
         }
     }
 
-    if cfg.convert_enabled && let Some(fmt) = cfg.convert_format {
-        job.convert = Some(pixstrip_core::operations::ConvertConfig::SingleFormat(fmt));
+    if cfg.convert_enabled {
+        // Check if any per-format mappings are set (non-zero = overridden)
+        let has_mapping = cfg.format_mapping_jpeg > 0
+            || cfg.format_mapping_png > 0
+            || cfg.format_mapping_webp > 0
+            || cfg.format_mapping_tiff > 0;
+
+        if has_mapping {
+            let mapping_to_format = |idx: u32, default: Option<pixstrip_core::types::ImageFormat>| -> Option<pixstrip_core::types::ImageFormat> {
+                match idx {
+                    1 => Some(pixstrip_core::types::ImageFormat::Jpeg),
+                    2 => Some(pixstrip_core::types::ImageFormat::Png),
+                    3 => Some(pixstrip_core::types::ImageFormat::WebP),
+                    4 => Some(pixstrip_core::types::ImageFormat::Avif),
+                    5 => None, // Keep Original
+                    _ => default, // "Same as above" - use global format
+                }
+            };
+
+            let global = cfg.convert_format;
+            let mut map = Vec::new();
+
+            // For each input format, determine output
+            let input_formats = [
+                (pixstrip_core::types::ImageFormat::Jpeg, cfg.format_mapping_jpeg),
+                (pixstrip_core::types::ImageFormat::Png, cfg.format_mapping_png),
+                (pixstrip_core::types::ImageFormat::WebP, cfg.format_mapping_webp),
+                (pixstrip_core::types::ImageFormat::Tiff, cfg.format_mapping_tiff),
+            ];
+
+            for (input_fmt, mapping_idx) in input_formats {
+                if let Some(output_fmt) = mapping_to_format(mapping_idx, global) {
+                    if output_fmt != input_fmt {
+                        map.push((input_fmt, output_fmt));
+                    }
+                }
+            }
+
+            if !map.is_empty() {
+                job.convert = Some(pixstrip_core::operations::ConvertConfig::FormatMapping(map));
+            }
+        } else if let Some(fmt) = cfg.convert_format {
+            job.convert = Some(pixstrip_core::operations::ConvertConfig::SingleFormat(fmt));
+        }
     }
 
     if cfg.compress_enabled {