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Merge branch 'color-matrix' into 'main'

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Color matrix node fixes & clarifications

See merge request GNOME/gtk!6290
This commit is contained in:
Benjamin Otte
2023-08-16 17:07:35 +00:00
parent 7d65f81d7f 246a7cfeab
commit 7d5ef1117e
2 changed files with 22 additions and 14 deletions
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7
gsk/gskrendernodeimpl.c
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@@ -3841,11 +3841,12 @@ gsk_color_matrix_node_class_init (gpointer g_class,
* Creates a `GskRenderNode` that will drawn the @child with
* @color_matrix.
*
* In particular, the node will transform the operation
* In particular, the node will transform colors by applying
*
* pixel = color_matrix * pixel + color_offset
* pixel = transpose(color_matrix) * pixel + color_offset
*
* for every pixel.
* for every pixel. The transformation operates on unpremultiplied
* colors, with color components ordered R, G, B, A.
*
* Returns: (transfer full) (type GskColorMatrixNode): A new `GskRenderNode`
*/

29
gtk/gtksnapshot.c
View File

@@ -567,29 +567,29 @@ merge_color_matrix_nodes (const graphene_matrix_t *matrix2,
const graphene_vec4_t *offset2,
GskRenderNode *child)
{
const graphene_matrix_t *mat1 = gsk_color_matrix_node_get_color_matrix (child);
const graphene_matrix_t *matrix1 = gsk_color_matrix_node_get_color_matrix (child);
const graphene_vec4_t *offset1 = gsk_color_matrix_node_get_color_offset (child);
graphene_matrix_t mat2 = *matrix2;
graphene_vec4_t off2 = *offset2;
graphene_matrix_t matrix;
graphene_vec4_t offset;
GskRenderNode *result;
g_assert (gsk_render_node_get_node_type (child) == GSK_COLOR_MATRIX_NODE);
/* color matrix node: color = mat * p + offset; for a pixel p.
* color = mat1 * (mat2 * p + offset2) + offset1;
* = mat1 * mat2 * p + offset2 * mat1 + offset1
* = (mat1 * mat2) * p + (offset2 * mat1 + offset1)
/* color matrix node: color = trans(mat) * p + offset; for a pixel p.
* color = trans(mat2) * (trans(mat1) * p + offset1) + offset2
* = trans(mat2) * trans(mat1) * p + trans(mat2) * offset1 + offset2
* = trans(mat1 * mat2) * p + (trans(mat2) * offset1 + offset2)
* Which this code does.
* mat1 and offset1 come from @child.
*/
graphene_matrix_transform_vec4 (mat1, offset2, &off2);
graphene_vec4_add (&off2, offset1, &off2);
graphene_matrix_transform_vec4 (matrix2, offset1, &offset);
graphene_vec4_add (&offset, offset2, &offset);
graphene_matrix_multiply (mat1, &mat2, &mat2);
graphene_matrix_multiply (matrix1, matrix2, &matrix);
result = gsk_color_matrix_node_new (gsk_color_matrix_node_get_child (child),
&mat2, &off2);
&matrix, &offset);
return result;
}
@@ -656,6 +656,13 @@ gtk_snapshot_collect_color_matrix (GtkSnapshot *snapshot,
* Modifies the colors of an image by applying an affine transformation
* in RGB space.
*
* In particular, the colors will be transformed by applying
*
* pixel = transpose(color_matrix) * pixel + color_offset
*
* for every pixel. The transformation operates on unpremultiplied
* colors, with color components ordered R, G, B, A.
*
* The image is recorded until the next call to [method@Gtk.Snapshot.pop].
*/
void