feat: Extracting picture data for raster images found in PPTX (#349)

* Added picture data for pptx pictures

Signed-off-by: Maksym Lysak <mly@zurich.ibm.com>

* Added tests for pptx

Signed-off-by: Maksym Lysak <mly@zurich.ibm.com>

* Inferring image DPI from pptx file

Signed-off-by: Maksym Lysak <mly@zurich.ibm.com>

---------

Signed-off-by: Maksym Lysak <mly@zurich.ibm.com>
Co-authored-by: Maksym Lysak <mly@zurich.ibm.com>

tests/data/groundtruth/docling_v2/powerpoint_sample.pptx.itxt

@@ -0,0 +1,35 @@
+item-0 at level 0: unspecified: group _root_
+  item-1 at level 1: chapter: group slide-0
+    item-2 at level 2: title: Test Table Slide
+    item-3 at level 2: paragraph: With footnote
+    item-4 at level 2: table with [9x7]
+  item-5 at level 1: chapter: group slide-1
+    item-6 at level 2: title: Second slide title
+    item-7 at level 2: paragraph: Let’s introduce a list
+    item-8 at level 2: paragraph: With foo
+    item-9 at level 2: paragraph: Bar
+    item-10 at level 2: paragraph: And baz things
+    item-11 at level 2: paragraph: A rectangle shape with this text inside.
+  item-12 at level 1: chapter: group slide-2
+    item-13 at level 2: ordered_list: group list
+      item-14 at level 3: list_item: List item4
+      item-15 at level 3: list_item: List item5
+      item-16 at level 3: list_item: List item6
+    item-17 at level 2: list: group list
+      item-18 at level 3: list_item: I1
+      item-19 at level 3: list_item: I2
+      item-20 at level 3: list_item: I3
+      item-21 at level 3: list_item: I4
+    item-22 at level 2: paragraph: Some info:
+    item-23 at level 2: list: group list
+      item-24 at level 3: list_item: Item A
+      item-25 at level 3: list_item: Item B
+    item-26 at level 2: paragraph: Maybe a list?
+    item-27 at level 2: ordered_list: group list
+      item-28 at level 3: list_item: List1
+      item-29 at level 3: list_item: List2
+      item-30 at level 3: list_item: List3
+    item-31 at level 2: list: group list
+      item-32 at level 3: list_item: l1 
+      item-33 at level 3: list_item: l2
+      item-34 at level 3: list_item: l3

tests/data/groundtruth/docling_v2/powerpoint_sample.pptx.md

@@ -0,0 +1,50 @@
+# Test Table Slide
+
+With footnote
+
+|    | Class1          | Class1          | Class1   | Class2   | Class2   | Class2   |
+|----|-----------------|-----------------|----------|----------|----------|----------|
+|    | A merged with B | A merged with B | C        | A        | B        | C        |
+| R1 | True            | False           |          | False    | True     | True     |
+| R2 |                 |                 | True     | False    |          |          |
+| R3 | False           |                 |          |          | False    |          |
+| R3 |                 | True            |          | True     |          |          |
+| R4 |                 |                 | False    |          | False    |          |
+| R4 |                 | True            |          | True     | False    | False    |
+| R4 | True            | False           | True     | False    | True     | False    |
+
+# Second slide title
+
+Let’s introduce a list
+
+With foo
+
+Bar
+
+And baz things
+
+A rectangle shape with this text inside.
+
+1. List item4
+2. List item5
+3. List item6
+
+- I1
+- I2
+- I3
+- I4
+
+Some info:
+
+- Item A
+- Item B
+
+Maybe a list?
+
+1. List1
+2. List2
+3. List3
+
+- l1 
+- l2
+- l3

tests/data/groundtruth/docling_v2/powerpoint_with_image.pptx.itxt

@@ -0,0 +1,5 @@
+item-0 at level 0: unspecified: group _root_
+  item-1 at level 1: chapter: group slide-0
+    item-2 at level 2: title: Docling
+    item-3 at level 2: paragraph: Image test
+    item-4 at level 2: picture

tests/data/groundtruth/docling_v2/powerpoint_with_image.pptx.md

@@ -0,0 +1,5 @@
+# Docling
+
+Image test
+
+<!-- image -->